The terrorists who changed air travel forever

The internet cafe where Abdulla Ahmed Ali sat down in front of a screen shortly before midday on 6 August 2006 was much like any of the hundreds of small communications shops that dot north-east London. T&I Telecom in Walthamstow offered the usual range of mobile phone top-up cards, cheap international calls and handsets alongside its row of pay-as-you-go internet terminals.

What set the shop apart that day was the presence alongside Ali, 27, of an undercover police officer who watched as his target went to the timetable page of the American Airlines website and began to highlight flight numbers. They were all heading from Heathrow to North America.

The information being collated by Ali was just one piece in a jigsaw of evidence that a plot covering three continents and led by the British-born Pakistani was moving rapidly towards its "execution phase". Equipped with technology bought from corner shops, a Welsh hairdressing wholesaler and an electrical store in Pakistan, a group of eight men – all young radicalised British Muslims – had carefully brought together a mission to cause death and destruction with homemade liquid explosives.

Ali would later admit to a plan to use liquid bombs concealed inside 500ml bottles of Oasis and Lucozade to target Terminal 3 at Heathrow. But police were concerned that an even more spectacular attack was being finalised: a suicide attack to simultaneously blow up at least seven – and as many as 18 – transatlantic airliners.

When the order came from within the British Government to arrest the gang late on 9 August, they were "just days" from launching the attack, according to police sources. One member of the cell was supposedly due to perform a "dummy run" within 72 hours to test airport security and surveillance tapes suggested that up to three more cells may have been involved in the plot, providing up to 10 more bombers.

It was a sophisticated and well-financed conspiracy which was first mooted in detail at least a year earlier in Pakistan by senior extremists with links to al- Qa'ida and was played out in internet cafes, in phone calls from kiosks using untraceable phone cards and late night meetings on street corners. At its centre was a two-bedroom flat on Forest Road, Walthamstow, bought for £138,000 in cash in July 2006 to act as a bomb factory.

From an Indian restaurant delivery driver to a former shop assistant, the plotters were a mixture of schoolfriends and acquaintances from the refugee camps of Pakistan who had honed their skills in bomb-making and had their resolve to become "shahid" or martyrs strengthened at extremist training camps in Pakistan over a period of at least four years.

The mission that Ali referred to as his "blessed operation" was brought together during a period of four months between April and early August 2006, rapidly reaching a peak of activity in its final three weeks.

Within hours of his visit to T&I Telecom, Ali met up with the second most important figure in the plot, Assad Ali Sarwar, the28-year-old "quartermaster" and chief target scout of the terrorist cell, who was based in High Wycombe, Buckinghamshire.

They met up with Mohammed Gulzar, a failed computer studies undergraduate, who prosecutors claimed had flown into Britain from South Africa to act as "supervisor" for the final stages of the plot. He was yesterday cleared by jurors of all charges.

Counter-terrorism sources claimed it was a measure of the "operational security" kept by the leaders that they chose to meet on a Walthamstow street corner where surveillance officers were unable to effectively eavesdrop. Within 72 hours of that meeting, the men were in custody, along with their fellow alleged conspirators.

Ali and Sarwar, who hid his formidable intelligence behind the facade of a bumbling university drop-out, were arrested as they sat on a wall together outside Waltham Forest Town Hall in north-east London at about 9.30pm on 9 August during a rendezvous set up in phone calls using untraceable calling cards.

When officers asked Sarwar, who had begun buying the supplies to make the liquid devices in April, if he had anything dangerous in his car – a red Nissan Primera – he had the chutzpah to reply: "Only the handbrake."

In reality, the contents of the quartermaster's car boot – and the pockets of his comrade – were considerably more sinister. In the boot were two of the six "suicide" videos recorded by the would-be bombers.

One of the two videos had been recorded hours earlier by Umar Islam, 30, aka Brian Young, a former postman and Rastafarian from High Wycombe who converted to Islam in 2001, in the Forest Road flat under Ali's direction and overheard by police. Islam said: "This is revenge for the actions of the US in the Muslim lands and their accomplices such as the British and the Jews."

Ultimately, the jury were unable to decide whether the "martyrdom" videos made by Islam and two other defendants were genuine or, as they claimed, were fake recordings for a documentary being made by Ali.

When police searched the jacket pockets of Ali, they found a computer "thumb drive" or memory stick containing details of seven flights out of Heathrow to North America along similar lines to the data he had been collating at T&I Telecom shop along with information about hand luggage rules at BAA airports. In the opposite pocket was a diary, which contained such a treasure of information that prosecutors at Woolwich Crown Court described it as a "blueprint" for the attacks.

Ali and Sarwar were careful to ensure members of the cell did not all meet each other until the plot was ready to be carried out.

Among the notes discovered in Ali's diary were: "select date, five days before jet. all link up"; "calculate exact drops of tang"; "decide on which battery to use for D"; "one drink use, other keep in pocket, maybe will not get through machine"; and "dirty mag to distract".

The flights that were identified by Ali, who holds a computer engineering degree, were all scheduled to depart within two-and-a-half hours of each other from Terminal 3 to six cities in North America – San Francisco, Toronto, Montreal, Washington, New York and Chicago. Police believe they were chosen because they would provide a six-hour window in which all the flights would be airborne and vulnerable to a simultaneous suicide attack. The jets were operated by Air Canada, United Airlines and American Airlines – and involved Boeing 777, 767 or 763 jets capable of carrying between 241 and 285 people.

Diary pages in Ali's spidery handwriting gave details of how the gang expected to smuggle the bombs on to the aircraft, using pornography and condoms to divert attention from their carriers' intent and the devices.

At the heart of the plot was a modus operandi that had never been seen before by counter-terrorism forces around the world. Using hydrogen peroxide bought by Sarwar in April and July using the false name of Jona Lewis from a hairdressing supply store in Carmarthen, South Wales, the men planned to inject a liquid explosive charge into the bottom of empty 500ml bottles of Lucozade or Oasis drinks.

The charge, a mixture of concentrated hydrogen peroxide – prepared by Sarwar with such precision that he could recite the formula by heart – and a powdered soft drink called Tang – was to be squirted through the plastic nodule at the bottom of each bottle and the hole concealed with superglue.

Footage from a concealed camera placed inside Forest Road recorded Ali drilling holes in the bottom of the drink bottles.

Another defendant, Tanvir Hussain, was put in charge of making a powerful explosive, HMTD, to be placed in detonators fashioned from hollowed-out Toshiba batteries which had been bought especially for the purpose in Pakistan. The hole at the bottom was to be concealed with black foam.

In his role as the head of logistics, Sarwar, who had been scratching a living selling martial arts DVDs on eBay, was responsible for gathering the equipment needed to make the HMTD. He placed the materials in a suitcase and buried them in woodland close to his home.

The group claimed the devices, along with their suicide videos, were part of a plan for a publicity campaign that would have involved setting off a "big bang" in the Houses of Parliament, later changed to Heathrow's Terminal 3, and the release of a spoof documentary containing the videos. Ali's defence barrister, Nadine Radford QC, insisted that the videos were of so unconvincing that they were not worthy of an appearance on The X Factor.

But experts declared the liquid bombs "highly viable", stating it was likely the devices would be set off with a power source such as the flash from a disposable camera and the resulting blast could have been powerful enough to rip a hole in the pressurised fuselage of a jet flying at a cruising altitude of 35,000ft.

One senior investigating officer told The Independent: "It was a clever and dastardly plot. We hadn't seen the like of it before. They had found a sophisticated way of concealing a device and we don't know if airport security would have been able to spot it."

By failing to convict Ali, Sarwar and Hussain of conspiring to target aircraft, the jury decided there was insufficient proof that downing airliners had been the finalised target of the plot.

Unknown to the plotters, every move had been watched by Scotland Yard's counter-terrorism command and MI5 from late April 2006 in the largest surveillance operation carried out in Britain, involving 200 specialist plain clothes officers drafted in from forces around the country.

Over a period of many weeks, undoubtedly with the benefit of Secret Service telephone taps, police pieced together the history of the conspiracy, tracing repeated calls to suspected al-Qa'ida contacts in Pakistan.

It was found that Ali and Sarwar had been involved with the Islamic spiritualist sect Tablighi Jamaat, which has been described by French intelligence as an "antechamber to terrorism" – a charge fiercely denied by its leaders.

But it was not until the final days of the investigation that police became fully aware of the breathtaking scope of what they believed Ali and his fellow conspirators were planning. Initial planning, carried out by Sarwar, had looked at "targets of national and regional significance", including Canary Wharf, a gas pipeline between Belgium and the UK and various UK airports and power stations, including nuclear facilities.

Bugged conversations suggested in July that the plot involved jets but police understanding of the plot was transformed in a whirlwind 72 hours beginning on 6 August.

Around the time that Ali was seen collecting flight details at T&I Telecom, the officers watching Sarwar, saw him disposing of empty bottles of hydrogen peroxide – the hairdressing bleach that was a key ingredient of the explosives detonated during the 7 July attacks on London in 2005.

Via a separate intelligence source, the detectives learned that a dummy run by one of the cell members, probably to test whether the liquid explosives could be detected by existing airport security checks, was planned in the coming days.

When the officers in charge of monitoring the bugged conversations at Forest Road heard another of the plotters recording an apparent suicide video it was decided the police could wait no longer.

A police source said: "We believed they were within days of executing the plot. A lot of elements came together to make it clear what was happening."

By the morning of 10 August, some 25 were in custody and a sudden ban was imposed on the carrying of any liquids in hand luggage on aircraft, sparking chaos and long delays at airports as well as the baggage restrictions that remain in place to this day.

When officers searched the home Ali shared with his wife and their infant son, they found a document on which he had written the philosophy that inspired his deeds. He wrote: "The psychology of war is that you can defeat your enemy if you take away that which they love the most and strike terror into their hearts. With martyrdom operations they achieve that as the most beloved thing is life and wealth. When your enemy is not scared to die it scares you."

The leader: Abdulla Ahmed Ali, 27

One of eight children, Ali was the charismatic ring leader or "emir" of the cell. He went to school in Walthamstow, north-east London, and was responsible for initiating contact with Sarwar in High Wycombe, Buckinghamshire.

After obtaining a degree in computer systems engineering from City University in 2002, Ali, who was born in Newham, east London, drifted between voluntary jobs and his increasing interest in radical Islam. He is thought to have been radicalised during a six-month trip to Pakistan when he visited an Afghan refugee camp.

On his return, he married and the couple had a baby boy in February 2004. The infant was born prematurely with a brain deformity and died, leading to suggestions that he might have had post-traumatic stress disorder. He made further trips to Pakistan where he is understood to have been selected to head the suicide plot and received training in how to build the devices.

The quartermaster: Assad Sarwar, 28

The plotter in charge of buying and formulating the main ingredients for the bombs was working as a delivery driver for an Indian restaurant and selling martial arts DVDs on eBay while participating in the plot.

While appearing a low-achieving misfit, Sarwar was engaged in reconnaissance for the cell, collating information on power stations and oil refineries. He even obtained a detailed map of security measures at a gas terminal in Norfolk.

Born and raised in High Wycombe, he dropped out of a science degree at Brunel University and became increasingly devout. He attended the same refugee camp as Ali in 2002 before returning to Pakistan in 2005 and 2006, where he is believed to have been trained in bomb-making.

Police found 18 litres of hydrogen peroxide and other key components for the devices in his possession. He was not take part in the mission, but was the custodian of the six other members' "suicide videos".

The lieutenant: Tanvir Hussain, 27

Hussain acted as Ali's "right-hand man" in the plot and was responsible for building the detonators that were hidden in the AA batteries that were to be used in the devices.

Born in Blackburn, Lancashire, he first met Ali while studying at Waltham Forest College, Essex, in his late teens. He told the court he regularly used drugs and alcohol during his student years before becoming devout while working at a NHS sexual health clinic in north London.

He travelled to Pakistan early in 2006, where he was instructed on how to make the HMTD, the high explosive to have been used in the detonators. Police found a suitcase of HTMD ingredients buried in Assad Sarwar's garden when they arrested him. During his trial, Hussain insisted he remained a "fun-loving guy" disinterested any terror plot. But fragments of the script for his suicide video revealed his "ultimate goal ... of becoming a martyr".