The Rest Is Classified

Episode 125: Al Qaeda’s Deadliest Plot: How MI5 Stopped Another 9/11 (Ep 1)
Hosts: David McCloskey & Gordon Corera
Release Date: February 9, 2026

Episode Overview

In this gripping series opener, David McCloskey and Gordon Corera uncover the inside story of MI5’s race to prevent a devastating al Qaeda plot: an attempt to blow up transatlantic airliners using homemade “liquid bombs.” This is the attack that led to global restrictions on carrying liquids on planes. Through newly-revealed details and interviews (including with former MI5 chief Jonathan Evans), the hosts walk listeners through the high-stakes surveillance operation—from mysterious luggage at Heathrow to shady activity in East London flats. This episode focuses on how the plot came to MI5's attention and the extraordinary surveillance and covert entry techniques used to piece it all together.

Key Discussion Points and Insights

1. The "Liquid Bomb Plot"—Context and Stakes

• The episode introduces the plot as one “that could have been worse than the 9/11 attacks, killing thousands” ([00:55], McCloskey).
• Originated from a flat in East London, the conspiracy planned to blow up multiple airliners bound for North America using explosives disguised as everyday liquids.
• Its aftermath explains current airport liquid restrictions. “If you’re wondering why you can’t take liquids on planes... this story is exactly the reason for that” ([02:00], McCloskey).

Quote

• “It is about what was assessed by Britain's security service, MI5 as the most dangerous terrorist conspiracy in British history.” ([02:31], Correra)

2. MI5 vs CIA—The ‘Special Relationship’ Under Pressure

• The case is described as a study in both cooperation and tension between UK and US intelligence agencies.
• They describe “incredible detail... some of the tension amid the cooperation between MI5 and the CIA in particular” ([03:28], McCloskey).

Notable Exchange

• Corera characterizes the fallout with the Americans: “...it really pisses off, to use a British phrase, the Brits in this case.” ([04:30], Correra)
• McCloskey counters: “...it also shows the value of the liaison relationship at the same time... the sum of the parts adds up to a lot more than the individual pieces...” ([04:52], McCloskey)

3. How MI5 Got on the Trail

Abdullah Ahmed Ali’s Suspicious Luggage

• The investigation begins at Heathrow (June 24, 2006) when Ali’s luggage from Pakistan is covertly searched by MI5—revealing batteries and powdered drink mix (Tang), both odd but not immediately alarming ([07:58]–[09:09]).
• “So it's a bit of a mystery as to why these things are in the luggage, but it's going to kick start an investigation which in just six weeks is going to go up to the top reaches of MI5, the White House, Downing street and Islamabad.” ([09:09], Correra)

Ali’s Profile and Radicalization

• British-born, with ties to Pakistan. He grows increasingly religious and political post-9/11, eventually coming on MI5’s radar for potentially funding extremist groups ([09:21]–[12:24]).

Quote

• “By about 2005, Ali is on MI5's radar for sending money to extremists... But it's not clear how dangerous he is, but it is suggestive, I guess, and enough for them to start a surveillance operation.” ([14:08], Correra)

4. Surveillance and Tradecraft

Following Lion Roar and His Network

• Ali receives the codename “Lion Roar” (“a really positive codename for a guy who’s being investigated”–[14:57], McCloskey).
• MI5 deploys its “A4” surveillance teams—diverse watchers who blend seamlessly: “young, old, every ethnicity... follow someone on the streets without being noticed.” ([16:14], Correra)
• The team observes odd shopping trips for electronics, attempts to get loans, and meticulous attention to bottles and caps in supermarkets ([17:34]–[19:31]).

Surveillance Evasion and Odd Behavior

• Ali and associates exhibit amateur counter-surveillance: “He’s kind of surveillance... aware or conscious. So they see him doing stuff like look around, turning suddenly, you know, trying to watch over his shoulder using mirrors...” ([16:54], Correra)
• At one point, Ali meets compatriot Asad Sawah in a local park, lying on the grass facing each other with hands over their mouths to avoid lip-reading ([19:51]–[20:55]).

Quote

• “If you Arrangement would be bizarre.” ([20:40], McCloskey)
• “Which attracts surveillance... So it's kind of... I don't know. I find it really interesting, a way of acting.” ([20:55], Correra)

5. Warning Signs—Purchases and Behavior

• Sawah (codenamed “Rich Food”), returning from Pakistan, buys small amounts of hydrogen peroxide—the ingredient in 7/7’s bombs—attempting to hide them with amateurish efforts, even googling ‘how to dig a hole’ ([21:26]–[22:36]).
• “He Googled that.” ([22:33], McCloskey)
• The group accumulates odd materials: syringes, drills, latex gloves, along with making attempts to secure a run-down flat for clandestine use ([23:45]–[24:28]).

6. Establishing “The Lab”—The Forest Road Flat

• July 20: Ali gets keys to a maisonette at 386A Forest Road, their would-be workshop for bomb assembly ([23:45]–[24:28]).
• He visits a “spy store” to buy intruder detection cameras—unusual at the time, highlighting his security concerns ([24:28]–[25:10]).

Quote

• “Back then you had to go to something called the spy store. Now we're all just letting everybody and their mother spy on us willingly by ourselves.” ([24:46]–[24:50], McCloskey)

7. Covert Entry—MI5’s Secret ‘Lawful Burglars’

Planning the Break-In

• MI5 deems it essential to get inside the flat, but launching a “covert entry” (not ‘breaking and entering’, as former MI5 chief Evans insists) requires careful planning: establish patterns, ensure nobody returns mid-op, and avoid detection by neighbors ([27:08]–[29:30]).

Teamwork and Skills

• The entry crew must include: locksmiths, technical installers (for bugs/cameras), and bomb disposal experts—all legally authorized to “do a bit of light breaking and entering” ([28:44], McCloskey).
• The process is likened to a high-stakes puzzle, with McCloskey referencing the CIA’s equivalent team as “essentially like choir boys... you cannot have a criminal record and do this kind of work.” ([30:09], McCloskey).

8. Behind the Scenes—Locks, Bugs, and Burglar Tricks

• A well-known saying: “You don’t pick a lock, you make a key” ([32:48], McCloskey)—the aim is persistent, undetected access to suspect properties.
• The team must also avoid leaving forensic or visual clues they were ever there. They often photograph or video the site on entry to replace everything exactly ([42:25]–[42:47]).
• The covert entry yields the installation of audio (and, after several attempts, video) surveillance devices in the Forest Road flat ([41:26]–[43:34]).

Quote

• “[When] they see the gloopy stuff, ‘why don’t you touch it?’... Cut the blue wire. It’s like it’s a bomb... at one point you hear one of them say on the video, ‘I effing love my job.’” ([38:49]–[38:54], Correra)

9. Breakthrough—Surveillance Brings Clarity

• With audio/video coverage, MI5 can finally discern the plotters’ real activities and intentions inside the flat; this critical intelligence will ultimately allow them to avert the mass-casualty plot ([43:34], McCloskey).
• Episode ends in suspense: “They’re gonna see something very strange. Very strange and very disturbing.” ([43:34]–[43:39])

Notable Quotes & Memorable Moments

| Timestamp | Quote | Speaker | |-----------|-------|---------| | 02:31 | "It is about what was assessed by Britain's security service, MI5 as the most dangerous terrorist conspiracy in British history." | Gordon Correra | | 04:30 | "It really pisses off, to use a British phrase, the Brits in this case." | Gordon Correra | | 14:57 | "They give him a code name. Yeah. Lion Roar." | Gordon Correra | | 20:40 | "If you Arrangement would be bizarre." | David McCloskey | | 22:33 | "He Googled that." | David McCloskey | | 24:46 | "Back then you had to go to something called the spy store. Now we're all just letting everybody and their mother spy on us willingly by ourselves." | David McCloskey | | 28:44 | "I don't think they'd be offended if we called them lawful burglars, do you?" | Gordon Correra | | 30:09 | "You cannot have a criminal record and do this kind of work." | David McCloskey | | 32:48 | "You don't pick a lock, you make a key." | David McCloskey | | 38:54 | "I effing love my job." | Unnamed MI5 team member, quoted by Correra |

Timestamps for Critical Segments

• 00:55 – Introduction of the “liquid bomb” plot and its legacy.
• 02:31 – MI5’s assessment of the threat.
• 07:58 – Heathrow incident: MI5 searches Ali’s baggage.
• 14:57 – Ali’s surveillance operation and codename.
• 19:51 – Odd meeting in Lloyd Park, counter-surveillance tactics.
• 22:36 – Amateur bomb-ingredient stockpiling and “how to dig a hole.”
• 24:28 – Acquisition of the Forest Road flat and “spy store” visit.
• 27:08 – Deep dive: Planning and executing MI5’s covert entry.
• 38:49 – Covert team’s finds inside the flat, banter, and surveillance setup.
• 43:34 – Surveillance breakthrough: what MI5 finally sees and hears.
• 43:39 – Episode cliffhanger/set-up for part 2.

Summary and Tone

This episode balances the seriousness of terrorism and national security with the dry humor and lived experience of two intelligence veterans, offering unique technical details and sharp personal anecdotes. The conversation is natural and insightful, delving into both the thrilling and mundane of spycraft. British and American linguistic and operational differences get friendly ribbing, real-life tradecraft is demystified, and listeners are left with a tense cliffhanger promising deeper revelations in episode two.

For a full immersion—including interviews with Sir Jonathan Evans, internal MI5 banter, and further revelations on one of Britain's gravest terror plots—listeners are invited to subscribe or join the show’s Declassified Club.