Could a 2% wealth tax raise £24bn?

Summary

More or Less: Behind the Stats

Episode: "Could a 2% wealth tax raise £24bn?"

Date: March 26, 2025
Host: Tim Harford, BBC Radio 4

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Episode Overview

This episode puts a spotlight on a claim made by Labour MP Diane Abbott that a 2% annual wealth tax on assets over £10 million could generate £24 billion a year for the UK. Tim Harford and the More or Less team investigate the validity of this statistic, delving into the math behind it, the practicalities and international context of wealth taxes, and the broader debate about taxing the wealthy. The episode also explores the challenges of implementing such a tax and discusses alternative taxation reforms. Other segments cover topics like the age of Britain's housing stock, ONS changes affecting national wealth statistics, and the surprisingly fluid calculation of the length of Lent.

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Main Segment: Could a 2% Wealth Tax Raise £24bn?

(01:44–10:16)

1. Where Does the £24bn Figure Come From?

• Diane Abbott cited this figure on BBC Radio 4’s Today Programme, suggesting a 2% tax on wealth over £10 million would raise £24bn annually.
• The origin is a 2020 Wealth Tax Commission report, authored by Arun Advani, Emma Chamberlain, and Andy Summers.
• The £24bn estimate is an extrapolation based on an annual 2% tax on qualifying wealth. This calculation is grounded in serious research, though the commission did not specifically recommend such a tax.

Tim Harford (02:30): "The £24 billion is a fair extrapolation from calculations the commission made, so there is some proper maths behind it."

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2. What Counts as Wealth?

• Dr. Arun Advani (03:49) emphasizes, for a wealth tax to work, all assets must be taxed equally: housing, pensions, business assets, etc., with no exemptions.

Dr. Arun Advani (03:49): "You are taxing houses, you are taxing pensions, you are taxing business wealth ... all of the full value of wealth."

• Exemptions are "kryptonite" for wealth taxes; the wealthy redirect resources into exempted assets, undermining tax revenue and fairness.

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3. The Practical Challenge: Exemptions & International Evidence

• Exemptions and special treatment have consistently undermined wealth taxes internationally.
• Dan Needle, former lawyer and head of Tax Policy Associates, is skeptical that an exemption-free wealth tax is achievable.

Dan Needle (05:34): "There's no wealth tax in the world that works like that."

Tim Harford (05:37): "Why not?"

Dan Needle (05:38): "There have always been exemptions, limitations, restrictions ..."

• Politically, influential business owners frequently succeed in lobbying for exemptions, weakening the tax and shifting the burden onto the merely affluent.
• Cites France as an example: exempted business assets, resulting in less revenue; later abolished the tax (06:34).

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4. Lessons from Other Countries

• Dr. Advani (06:58): UK as "second mover" can learn from global mistakes—mainly that exemptions or loopholes drastically reduce effectiveness.

Dr. Arun Advani (06:58): "At some point, if you want one, you have to build it properly. And if you're not going to build it properly, it's not worth doing."

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5. Avoidance & Revenue Loss

• Even a well-designed tax would face avoidance, notably by the ultra-wealthy changing residency.
• Wealth Tax Commission estimated 7–17% of the tax base could be lost to avoidance at a 1% rate (07:22).

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6. Annual vs. One-Off Wealth Tax

• A one-off wealth tax, implemented as a surprise, would face less avoidance than an annual levy—though it’s a one-time windfall.
• Dr. Advani and Dan Needle both agree a one-off is more effective post-shock (e.g. after COVID), but less suitable for ongoing funding (08:47).

Dr. Arun Advani (08:47): "The best solution ... would have been a one off wealth tax rather than either an annual wealth tax or rather than say a change in income tax or national insurance contributions."

• Annual taxes covering a large population are not favored; recommend fixing existing taxes on wealth (like capital gains) instead.

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7. Alternatives: Improving Existing Wealth Taxes

• Dan Needle enumerates broken aspects of land taxes, stamp duty, capital gains conversions, and inheritance tax avoidance.
• Argues for political will to enforce existingwealth taxation rather than inventing a new tax.

Dan Needle (09:48): "If there was the political will to tax wealth more effectively, we could do it. But you don't need a wealth tax to do that."

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Key Quotes & Timestamps

| Time | Speaker | Quote | |---------|-----------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------| | 02:30 | Tim Harford | "The £24 billion is a fair extrapolation... so there is some proper maths behind it." | | 03:49 | Dr. Arun Advani | "You are taxing houses, you are taxing pensions, you are taxing business wealth ... all of the full value of wealth." | | 05:34 | Dan Needle | "There's no wealth tax in the world that works like that." | | 06:58 | Dr. Arun Advani | "At some point, if you want one, you have to build it properly. And if you're not going to build it properly, it's not worth doing." | | 08:47 | Dr. Arun Advani | "...the best solution ... would have been a one off wealth tax rather than either an annual wealth tax or... a change in income tax or national insurance." | | 09:48 | Dan Needle | "If there was the political will to tax wealth more effectively, we could do it. But you don't need a wealth tax to do that." |

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Additional Content

Britain's Old Housing Stock

(12:24–18:07)

Key Points

• The UK has the oldest housing stock in Europe: 38% of homes built before 1946 (EU average: 22%).
• Historical context: Industrial Revolution saw a boom in terraced housing, most still standing today.
• Post-war building surge (semi-detached houses), but house building rates have dropped dramatically since the 1970s.
• Why it matters: Older housing is less energy-efficient and difficult to retrofit; old stock is a symptom of not building enough new homes.

Notable Quotes

Jane Goddard (14:41): "If you wanted to pull down a street of terraces ... you would have to get permission from every single person in that street."

Jane Goddard (17:49): "1.5 million homes is a relatively small increase ... as we already have something in the order of 80% of the housing stock that will still be here in 2050."

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ONS, Flawed Accounting, and Missing £2 Trillion

(19:58–25:05)

Key Points

• Media claim: ONS made the UK £2 trillion poorer through accounting changes.
• Reality: No one lost wealth; the ONS revised its method for valuing pension wealth, reducing the official number.
• IFS economist Stuart Adam says the new method undervalues pensions by using GDP growth instead of market interest rates.
• Takeaway: Wealth statistics are volatile and methods matter, but actual pensions haven’t changed.

Stuart Adam (22:04): "They estimate that pension wealth is over a third lower than they previously thought."

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The Length of Lent: 40 Days, 46 Days, or Something Else?

(26:35–30:41)

Key Points

• The period of Lent varies historically and denominationally: 40, 46, or even 55 days.
• Sundays are often not counted in fasting, causing confusion.
• The number 40 is symbolic in biblical tradition, not always literal.
• Expert Prof. Alison Salverson links "40" to major biblical events, e.g., Moses on Sinai.

Professor Alison Salverson (29:19): "40 is not a literal number ... It takes on a kind of symbolic and elusive value."

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Memorable Moments

• Tim Harford’s dry humor surfaces when discussing celebrity farmland buying and Jeremy Clarkson (04:20), and again in referencing the Council of Elrond while discussing Lent (27:32).
• The recurring motif that practical implementation always falls short of neat academic theory, especially for wealth taxes and national accounting.

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Timestamps — Main Segments

• 01:44 – 10:16: Wealth tax discussion: origin, feasibility, and alternatives
• 12:24 – 18:07: Why are British houses so old?
• 19:58 – 25:05: ONS, accounting changes, and the £2 trillion wealth debate
• 26:35 – 30:41: How long is Lent, really? Biblical numeracy and symbolism

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Conclusion

The £24bn figure for a 2% wealth tax is plausible as a mathematical extrapolation only if the tax applies without exemptions — a scenario not observed in any real-world example. Enacting such a tax is fraught with political and practical challenges, and history shows the very wealthy often escape the bite. The show ultimately points toward reforming existing wealth taxes and closing known loopholes as more effective and politically feasible routes for the UK. The episode also reinforces that both statistical measures and religious traditions are more about convention and symbolism than hard, unchangeable facts.

Transcript

[Tim Harford]

This BBC podcast is supported by ads outside the uk. You can make a difference in someone's life, including your own, with a job in home care. These jobs offer flexible schedules, health care, retirement options and free training. They also provide paid time off and opportunities for overtime. Visit oregonhomecarejobs.com to learn more and apply. That's oregonhomecarejobs.com.

[Izzy Judd]

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[Tim Harford]

BBC.

[Lizzie McNeil]

Sounds music radio podcasts hello and welcome.

[Tim Harford]

To More or Less. Wherever there's a top secret group chat about numbers, you can bet that we're lurking unobserved and taking notes. I'm Tim Harford. This week we resolve last week's low jeopardy cliffhanger about why British houses are really old. We investigate claims that the Office for National statistics have stuffed £2 trillion into a duffel bag and absconded to Brazil. We return to the increasingly recondite topic of how many days there are in Lent. But first, last week the Government announced changes to the disability benefits system, which included cuts aimed at saving 5 billion pounds a year. The move was met with dismay by some, including those on the left of the Labour party, such as MP Diane Abbott. She appeared on Radio 4's Today programme and argued that there was another way to deal with the financial pressures of a rising disability benefits bill. I would introduce a wealth tax. If you brought in a wealth tax of just 2% on people with assets over 10 million pounds, that would raise 24 billion a year. That's what I would do. Loyal listeners have been in touch asking us to look into this figure. So we tracked it down. It ultimately comes from the Wealth Tax Commission, an independent report written in 2020 by academics and experts led by Aaron Advani, Emma Chamberlain and Andy Summers. I wonder what had happened to him. The report looked at whether a wealth tax would be a plausible way to pay for the one off cost of responding to the pandemic. This 24 billion pound figure is based on levying an annual tax of 2% on any wealth over 10 million pounds. The wealth tax Commission didn't argue for this rate or threshold, but the £24 billion is a fair extrapolation from calculations the commission made, so there is some proper maths behind it. But what do we mean by wealth? Dr. Arun Advani was one of the commissioners of the report, as well as being an economist and the director of the Centre for the Analysis of Taxation.

[Dr. Arun Advani]

One of the things we said that was crucial if you were going to have a wealth tax, was that you treat all assets equally. That means you are taxing houses, you are taxing pensions, you are taxing business wealth. If that's what you hold, you're taxing all of the full value of wealth.

[Tim Harford]

So the kind of wealth tax envisaged by Arun Advani would encompass all forms of wealth, no exemptions. And there is a reason for that. Exemptions are kryptonite for wealth taxes. The ultra wealthy tend to be well advised and if one kind of asset is excluded or taxed at a lower rate, then they will put all of their money into. Into that. Say that an exemption was made for farmland or forestry. All of a sudden you'd see rich people buying forestry and farmland. We are looking at you, Mr. Clarkson. Classic BBC there. Classic. Oh, yeah. Actually, this gratuitous celebrity reference is making a point. It sounds easy not to have exemptions, but as the protests over farms and inheritance tax show, it isn't easy. And this has consequences.

[Dr. Arun Advani]

So when you look at other countries where sometimes the revenue estimates have been a bit disappointing and the money that comes in is lower, you can see that one of the biggest, or the biggest reason for that is that they all have ended up with gaps in their wealth tax. Certain assets that aren't being taxed, and then people naturally shift over to those assets or find ways to value those assets creatively as ways of reducing the taxable wealth that they have.

[Tim Harford]

We see this in the real world. Many a wealth tax has been brought low by the addition of exemptions or special treatment. Dan Needle is a former top tax lawyer who now runs a tax think tank, Tax Policy Associates. He thinks the international evidence shows us that wealth taxes are never as simple as the theory would have it.

[Dan Needle]

There's no wealth tax in the world that works like that.

[Tim Harford]

Why not?

[Dan Needle]

There have always been exemptions, limitations, restrictions, qualifications as there are for all taxes.

[Tim Harford]

And is that because people always lobby or. Well, I'm sure it's partly because people always lobby, but is it because for some economic or legal reason, it's just impossible to levy a wealth tax like that?

[Dan Needle]

Well, there's two ways to put it, and you can pick the one you prefer. The first one is that there will be economic inefficiency or even injustice if someone is taxed at a level that means they have to dispose of their business. The alternative way to view that is that people who own large businesses are in an excellent position to lobby and they create exemptions for themselves. Whichever one of those is true, they, in a way, doesn't matter much because the history has been that wealth taxes have bloody great exceptions and so the very wealthy have ended up not paying much and the mere upper middle class, if you like, ends up paying it.

[Tim Harford]

The international evidence is indeed not hugely promising. Back in 1990, there were 12 OECD countries that levied annual wealth taxes. Today it's just three. France, for example, introduced an annual wealth tax but exempted business assets. It ended up abolishing the tax in 2018. I asked Arun Advani about the international evidence.

[Dr. Arun Advani]

I think one kind of advantage for us as a sort of second mover in this context is that other countries have built wealth taxes before and they've made mistakes before, and we can see what the costs of those mistakes are. So we can say, Look, Mr. Or Mrs. Policymaker, if you are in a world in which you're going to go out there and build a wealth tax, this is going to be the cost of allowing some of those gaps in the wealth tax. And at some point, if you want one, you have to build it properly. And if you're not going to build it properly, it's not worth doing.

[Tim Harford]

But even if you did design it perfectly, would it bring in £24 billion a year? There would still be ways to avoid paying that tax, such as spending so little time in the UK that you are no longer eligible. The Wealth Tax Commission did look at international evidence on how much revenue might be lost to avoidance. If the tax rate levied was 1%, they thought between 7 and 17% of the initial tax base would be lost. It is tricky, though. International wealth taxes have tended to kick in at relatively low thresholds, certainly when compared to this proposed UK version. Much of the recent discussion has centred around the idea of whether an annual wealth tax would work or not. But. But there are other options. The government could, for example, implement a one off wealth tax levied just the once. Both Aaron Advani and Dan Needle agree that that would face fewer of the difficulties around avoidance that an annual wealth tax would. As long as it takes people by surprise, the super rich wouldn't be able to change their behaviour. Though of course this wouldn't give you an ongoing source of income and the super rich might not believe the tax would be a one off and start thinking of avoidance strategies anyway. Aaron spent a long time looking at the evidence on wealth taxes. So what did he and his colleagues end up recommending?

[Dr. Arun Advani]

So what we said at the end of the work that we did, given that it was in the context of COVID was that to pay for that one off shock that we'd had, the best solution, both in the context of wealth taxes, but also in the context of taxes more generally, would have been a one off wealth tax rather than either an annual wealth tax or rather than say a change in income tax or national insurance contributions. We separately said that if you're in the space of thinking about annual wealth taxes, certainly we would not recommend an annual wealth tax starting at a low threshold, meaning covering a large share of the population. We have other taxes on wealth in this country, like capital gains tax, that don't work very well and we thought it'd be much easier and much more sensible to fix those. But we also said if you have a desire to get revenue specifically from the very wealthiest, if that was your political goal, then you could operate an annual wealth tax. It is possible to make it work. You should be aware that it's not trivial, but it is doable.

[Tim Harford]

Rather than a new wealth tax, Dan Needle is in favour of reforming the taxes the government already levies on wealth.

[Dan Needle]

So yes, we could fix all our rather broken land taxes, stamp duty, council tax, business rates. We could stop people converting income tax to 45% at the top rate into capital gains taxed at 24%. We could stop the widespread avoidance of inheritance tax by the very wealthy and these problems are known and if there was the political will to tax wealth more effectively, we could do it. But you don't need a wealth tax to do that.

[Tim Harford]

Our thanks to Dr. Aaron Advani and Dan Needle. Dan is presenting a new series on Radio 4 called Untaxing about how Tax has shaped the world around us. It's on at 1:45 every day. Next week. You're listening to More or Less. Cometh the hour, cometh the Man. Last week, Keir Starmer was defending the government's economic record at Prime Minister's questions, which, as you might expect, included a fair bit of attacking the Conservatives record. That's after only eight months. After 14 years of absolute failure, what do they do? Interest rates 11%. Interest rates at 11%. Keir Starmer has fallen into a time slip and found himself in the early 90s. That is right, kids, crack out that fancy new CD player in your Ford Fiesta. We are going back to 1991, the last time interest rates were at that level. So unless Keir has a long standing grudge against John Major, we presume that he meant to say inflation at 11%, which it did hit in October 2022. Now, we might have let this one go as a slip of the tongue, except the Labour Minister, Seema Malhotra, tweeted this clip and repeated the claim that interest rates had hit 11% under the recent Conservative government, which, of course, they didn'. Previously on More or Less. The question is, what is old? Is the word old being used in a pejorative sense? Old houses can be better than new ones. Last week, loyal listener Colin wanted us to investigate the claim that the UK has the oldest housing stock in Europe and to explain whether that was actually a bad thing. Great question, but we only had time for the lowest Jeopardy cliffhanger in broadcasting history. But now we are back with a full answer for Colin.

[Jane Goddard]

Yes, we do have the oldest housing stock in Europe and we know that because almost 50 years we've been monitoring the housing stock across the country.

[Tim Harford]

This is Jane Goddard, the Managing director of the Building Performance Services, part of bre, that is the Building Research Establishment, which conducts the housing survey for England. They're also involved with surveys in Wales, Scotland and Northern Ireland. And helpfully, there are similar surveys carried out across Europe. The results are the proportion of homes built before 1946. So more than 80 years ago. United Kingdom 38%. EU average 22%. The two countries in the EU whose housing is similarly old are Belgium and Denmark. The lowest on the table are Greece at 8% and Cyprus at 3%. And France, Germany and Italy are all between 20 and 30%. So why is the UK's housing stock so much older?

[Jane Goddard]

Principally, it was the Industrial Revolution which saw a lot of people moving from rural areas to urban areas. And that's why we see so Many Victorian houses, and we see so many terraced houses. Workers cott and that was really the proliferation of housing in this country.

[Tim Harford]

The Industrial Revolution got underway sooner in the UK than in other European countries. And this proliferation of terraced houses accounts for much of our oldest housing stock today. Cue classic BBC documentary. The bylaws made the terrace Britain's new model home. And over the course of the 19th century, a staggering 5 million were built. There are around 750,000 homes today which were built before 1850, but they make up only about 3% of the UK's 25 million homes. It was the rows and rows of terraced houses which continued to be built into the 20th century, which form a big chunk of the homes which are over a century old. The vast majority are still with us today. It's hard to get consensus to replace them.

[Jane Goddard]

If you wanted to pull down a street of terraces, for example, and I myself live in a terraced house, you would have to get permission from every single person in that street in order to bring that down and do something different with the housing.

[Tim Harford]

Anyway, even if we could get consensus, that consensus might well be, let's keep them.

[Jane Goddard]

Well, terraces were popular and still are, and we are very attached to our terraced housing.

[Tim Harford]

After the First World War, Britain embarked on a new wave of building. This was the era of the semi detached house. New accommodation under ideal conditions has already been provided for about 6,000 slum dwellers. Taken from slum properties like these to semi detached houses like these. The semi detached house and the terraced house are the most common property types in the uk. Would you believe that these houses are only a mile or two from the centre of Birmingham? No wonder the workers feel as if they had been reborn. Another 40% of our current housing stock was built between 1946 and 1980. This clip is from a new estate under construction in the 1950s. Built in 12 weeks for less than a thousand pounds each, these houses seem one answer to the housing drive. With the living room, dining annex and kitchen. Downstairs, they have three bedrooms. Upstairs, women will find their work has been made as simple as possible. That's because when he made the plans, architect Mr. Appleton asked housewife Mrs. Appleton for suggestions. Gosh. But this brief history of British house building starts to run thin from about 1970. House building rates, already below those of the interwar years, fell dramatically in the 1970s. And despite the occasional micro boom, they have been continuing to fall ever since. Fundamentally, that is why the average house is so old. Not because we have lots of old houses, but because we don't have many new ones. The situation in many Western European countries is different. Most of them have built a lot more since the war than the UK has one exception. Belgium has the same old housing stock as the UK does. But as loyal listener Colin asks, why does this matter? A lot of old housing is much loved. There are two reasons. The first is that old housing is often expensive to heat, bad for your pocketbook and bad for the planet. And retrofitting to improve insulation can also be difficult and expensive. Old houses can also underperform in other ways, for example, accessibility for elderly or disabled people. The second reason is not that old housing is a problem, but that it's a symptom. Our housing stock is old on average because we're not building many new homes and we haven't done for the last 50 years. And because we're not building many new homes, people can't afford a place to live. As many of you will have heard, the government has announced a new Drive to build 1 1/2 million new homes over the course of this Parliament. If achieved, will this make a huge difference to our overall housing stock?

[Jane Goddard]

In short, no, as we already have something in the order of 80% of the housing stock that will still be here in 2050 1.5 million homes is a relatively small increase in that number.

[Tim Harford]

In other words, the best time to modernise your housing stock was 50 years ago. The second best time is now. Don't expect the UK's housing stock to be modernized overnight.

[Lizzie McNeil]

You can make a difference in someone's.

[Tim Harford]

Life, including your own, with a job in home care.

[Lizzie McNeil]

These jobs offer flexible schedules, health care, retirement options and free training.

[Tim Harford]

They also provide paid time off and opportunities for overtime. Visit oregonhomecarejobs.com to learn more and apply.

[Izzy Judd]

That's oregonhomecarejobs.com running a business online. Look legit and own your own brand with professional tools from GoDaddy. Instantly build trust with your customers and boost your credibility with an email that matches your domain so people know you mean business. There's never been a better time. Just go to GoDaddy.com GDnow and and choose from a wide variety of popular domains. To find one that's right for you. Pair that with a professional email that works for all your business needs, from daily communications to email marketing and everything in between. That's a little price for a lot of credibility. For a limited time, get a domain and matching professional email for just 99 cents a month for one year. Go to GoDaddy.comGdNow and look legit with GoDaddy. That's GoDaddy.comGdNow again. GoDaddy.comGdNow there's never been a better time to choose the domain and email that's right for you. New customer purchases only products Auto renew separately See terms on site godaddy.com gdnow.

[Tim Harford]

We heard last week about the goings on at the Office for National Statistics and how their incredibly important labour force survey has gone quite wrong. While not content with that, the Telegraph seemed to be accusing them of accounting misdeeds to make Bernie Madoff, Sam Bankman, Fried and the Enron team look like small time operators. Britain's left £2 trillion worse off by flawed accounting change. £2 trillion worse off. Oh, ONS, what have you done? And to which tropical paradise have you run off with the money? For £2 trillion you are going to need a very big suitcase. The Telegraph story is based on a report from the Institute for Fiscal Studies co written by senior economist Stuart Adam. So how did the ONS manage to pull off this massive heist?

[Stuart Adam]

Well, fortunately, accounting changes can't actually make us worse off. What's happened is that the ons, the Office for National Statistics, has revised how well off they thought we already were. So it's not actually changing anyone's wealth, but it's changing its measure of people's wealth.

[Tim Harford]

Phew. So no individual Britain is actually worse off in reality, it's just that the ONS's estimate of how much we collectively have has fallen. The missing 2 trillion pounds is the result of a change in the way the ONS estimates the value of people's pensions. This is combined with attempts to put a value on other things, such as houses, to work out how much wealth we own between us. And the ONS also estimates who owns what, giving a wealth distribution and an estimate for wealth inequality in the uk. Now, for a lot of people, one of their biggest assets is their pension, which might be a big pot of cash, but it might also be an income from an annuity or a final salary pension. So how to value that? The ONS recently changed its approach and to show the nation's finest geeks their working has published estimates in using the new methodology and data from 2018 to 2020.

[Stuart Adam]

The overall effect of this is that they estimate that pension wealth is over a third lower than they previously thought. And because pensions are such a big part of people's overall wealth, that means that aggregate household wealth for Britain as a whole is 14% lower than they previously thought.

[Tim Harford]

It's a big shift in our estimated wealth. But the IFS thinks there's a mistake in the new methodology.

[Stuart Adam]

The biggest change the ONS has made is to change the way in which it converts future pension income into today's terms.

[Tim Harford]

This question doesn't have an easy answer, and figuring it out involves a few assumptions.

[Stuart Adam]

So if I've got a pension that pays me so many thousand pounds a year from now until I die, what's the value of that today? And one way you might go about answering that is to say, well, how much would I need to invest to to get the same annual income as I get from this pension? And the usual way you would go about that is to use an interest rate, because if interest rates are high, then I don't need very much money now to generate more income in future, whereas if interest rates are low, I can't get very much return on my savings. So what we do is we use an interest rate to convert that future stream of income into a lump sum value today.

[Tim Harford]

So if you're getting £1,000 a year as a pension, you'd need £100,000 in the bank to earn that. If interest rates were 1%. If they were 5%, then you'd only need £20,000. So we might say that your £1,000 a year pension is worth either £100,000 or £20,000, depending on the interest rate. Now, for a nation spanning estimate of wealth like this, there is plenty of debate to be had around precisely what interest rate you would use to calculate the value of these pensions. The ons, after a big review and lots of expert advice, went down a different path.

[Stuart Adam]

It's converting future income into today's terms, not using an interest rate at all, but using essentially a forecast of the rate of GDP growth, the rate at which national income can grow. And I can't see any reason why, why the rate of GDP growth should be relevant to valuing future pension income in today's terms. You should be using a market interest rate of some sort.

[Tim Harford]

The GDP growth rate is related to interest rates over the very long term, but in the short term they can be pretty far apart for the time period. The ONS looked at 2018-2020, interest rates were high and GDP growth was low. So changing the methodology made a big difference, reducing the estimated value by over.

[Stuart Adam]

£2 trillion across the population as a whole relative to using market interest rates.

[Tim Harford]

Perhaps the big takeaway here is that when you see estimates of the UK's wealth distribution in the news. You need to remember that this big debate is going on in the background. The number changes a lot depending on the ONS methodology and that means the political argument may change too. But one thing that hasn't changed the is your pension. Our thanks to Stuart Adam from the Institute for Fiscal Studies. While we're talking about the ons, they have also recently announced that they're pausing the publication of more statistics. The Producer Price Index and the Services Producer Price Indices. These track the inflation that's faced by producers of goods and services and they're used in the calculations for GDP Gross Domestic Product. Oh, at least GDP numbers aren't being used calculating any other stats, eh? We are still keen to talk to the ons and we are available for them to reach us via phone, email or Tinder. In our first episode of the series, which is available to download as a podcast, we did a short, playful item about Lent and how it's not actually 40 days long as we were led to believe, but 46 because Sundays aren't counted. Lent is still 40 days. Ish. We have received a lot of emails about this, so like Christ with Lazarus, we are raising this item back from the dead to discuss it further. And with me is our Biblical Numbers correspondent, Lizzie McNeil. Hello Lizzie.

[Lizzie McNeil]

Hi Tim. Well, let's take it back to the start. So, as we all know, Lent is celebrated to commemorate Jesus going to the wilderness for 40 days and nights, where he fasted and spent a lot of time resisting temptation. But the length of Lent has changed throughout the centuries. In the earlier days of Christianity, there was huge debate about how long lent was. As St. Irenaeus wrote to Pope St. Victor I in the third century AD.

[Tim Harford]

The dispute is not only about the day, but also about the actual character of the fast. Some think that they ought to fast for one day, some for two, others for still more. Some make their day last 40 hours on end. Such variation in the observance did not originate in our own day, but very much earlier in the time of our forefathers.

[Lizzie McNeil]

This was a problem that was eventually tackled by the Council of Nicaea in 325 AD, which is probably everyone's second favourite council after the Council.

[Tim Harford]

The Council of Elrond.

[Lizzie McNeil]

Exactly. Anyway, this is when Lent was first given its 40 day time frame. However, they didn't fast on Sundays, but did include Sundays in their count. So they only fasted for 34 out of the 40 days. Now, eventually the church split with two distinct branches, east and West, which led to even more variation in Jerusalem. For Instance, people fasted for 40 days Monday through Friday, but not on Saturday or Sunday, meaning Lent was a period of eight weeks in Rome. In the west, people fast Monday through Saturday, making their period of lent last for six weeks. If you're Ethiopian, the Great Lent lasts for 55 days. In Eastern Orthodoxy, Lent is 40 days and includes Sundays. Adding to the confusion, their Lent also generally starts at a different time to Western churches, as they use the Julian calendar rather than the Gregorian. So lent has lasted one day, three days, 40 days, 46 days, or 55 days, depending where you are in history, the world, and which denomination you follow.

[Dr. Arun Advani]

Right.

[Tim Harford]

So some people include Sundays, some don't include Sundays, some don't include Saturdays. There's a lot going on. But what about our comments about the number 40 actually being used in the Bible to mean quite a lot? Umpteen loads, Yeah.

[Lizzie McNeil]

I consulted a proper expert on this, Alison Salverson, professor of Early Judaism and Christianity at the University of Oxford and the Oxford center for Hebrew and Jewish Studies. She has, somewhat ironically, spent the last 40 years studying these religious texts, so has come across the number 40 quite a bit.

[Professor Alison Salverson]

It occurs in the Hebrew Bible, in particular the Old Testament for Christians, and it's highly symbolic.

[Lizzie McNeil]

She agreed that 40 is not a literal number, and it means a sort.

[Professor Alison Salverson]

Of significant length of time, usually, or a significant number, but not usually in a kind of literal sense. So 40 days does not necessarily mean almost six weeks, and 40 years does not necessarily mean exactly 40. It takes on a kind of symbolic and elusive value because it's used particularly of Moses on going up to Sinai and staying there, talking to God for 40 days and 40 nights and not eating or drinking, which I think is very significant for the Gospel passage. It's also used of Elijah's journey to Mount Horeb to meet with God as well. And that's supposed to have taken 40 days and 40 nights. And so when it's used in the New Testament, I think it's highly likely that the writers were very conscious of making a link with both Moses and Elijah, who were very significant figures for jews in the 1st century of the Common Era. And so when it says that Jesus was in the wilderness for 40 days, it's not an exact number. It is a round figure. But it also points very clearly to the episodes of Moses and Elijah in the Hebrew Bible. Meeting with God in the wilderness in a lonely place and not eating and drinking. So that is what we're meant to be thinking of, rather than some kind of countdown from 40.

[Tim Harford]

Thank you, Lizzie. And thanks to Professor Alison Salverson. And thanks also to everyone who wrote in. I hope we have answered your queries and now I feel more enlightened. And that's all we have time for this week, but we will be back next week with a triple decker sandwich of statistical news and comment. Something like that. Anyway, please keep your questions and your comments coming in to more or less BBC.co.uk. and until next week, goodbye. More or Less was presented by me, Tim Harford. The producer was Tom Coles with Nathan Gower, Charlotte MacDonald and Lizzie McNeil. Our production coordinator was Gemma Ashman. The programme was recorded and mixed by Gareth Jones and our editor is Richard Varden.

[Izzy Judd]

Hi, I'm Izzy Judd. Have you actually breathed properly yet today? If things are a bit hectic at the moment, if you're struggling to switch off from work, or if you're generally just feeling a bit stuck in life, I've got just the thing for you. Join me for the music and meditation podcast on BBC Sounds and Radio 3 Unwind. It's a place where we press pause with the help of some inspirational guests, wonderful guided meditations and stunning music. Honestly, I think you'll love it, so why not give it a go?

[Tim Harford]

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