London: A plot to blow up at least seven transatlantic aircraft using liquid bombs was masterminded from Pakistan, intelligence services said as more details emerged Tuesday of the complex planned attacks.
British police were forced to go to extraordinary lengths to build their case against the men who prosecutors say were hoping to cause more deaths than the September 11, 2001 attacks.
The trial, which ended in the convictions of three British Muslims on Monday, was peppered with evidence that members of the London-based gang were frequently in communication with figures linked to al Qaeda in Pakistan.
"In terms of al Qaeda involvement, there is a large part of this plot that has been thought through or invented in Pakistan," one senior counter-terrorism source said after the verdicts.
The jury were shown emails in which Abdulla Ahmed Ali, 28, Tanvir Hussain, 28, and Assad Sarwar, 29, asked Pakistani contacts for advice on building bombs disguised as drink bottles to detonate on flights over the Atlantic.
Prosecutors believe the absence of evidence establishing these links had led to a jury in the men`s first trial in 2008 failing to reach a verdict that they had plotted to blow up the planes, forcing a second trial to be held.
The emails were eventually obtained by a court order in California requiring Yahoo! to disclose them.
Ken MacDonald, Britain`s chief prosecutor at the time of the investigation, said: "We felt that this was a strong case from the start, unfortunately the jury in the first trial could not agree.
"The additional evidence that we had (in the second trial) were the emails," he told BBC radio.
Reports said the men`s main point of contact was Rashid Rauf, a British-born Muslim who fled to the tribal areas of Pakistan in 2002 after the murder of his uncle and developed strong links with al Qaeda.
Intelligence services also reportedly believe he was a key contact of the gang in the 2005 bombings of the London transport system which killed 52 people.
The trial heard that Ali had already been identified as a dangerous radical when he was stopped at Heathrow Airport in June 2006 on his return from a trip to Pakistan.
Customs officials found a large quantity of batteries and a high-sugar powdered drink in his luggage. Both are ingredients for homemade bombs.
He was not arrested, but police broke into his flat one night and installed hidden cameras and microphones.
Over the next few months, they watched as Ali and his colleagues experimented with injecting drinks bottles with a mixture of the explosive liquid hydrogen peroxide which they planned to carry on to flights and detonate with a bulb filament.
But the biggest counter-terrorism operation ever mounted in Britain, costing GBP 35 million, was reportedly almost thrown into jeopardy by US intervention.
Fearful that the gang were close to carrying out the plane bombings, the US authorities put pressure on Pakistan to arrest Rauf in 2006.
Andy Hayman, a senior police commander who worked on the case, said in the Times newspaper that his detention "hampered our evidence-gathering and placed us in Britain under intolerable pressure."
British police were confident that they had the gang completely under surveillance, but Rauf`s arrest forced them to bring forward the arrests in Britain before the gang were alerted that their plot had been uncovered.
John McDowall, head of the Counter-Terrorism Command of London`s Metropolitan Police, said of the London gang`s arrest: "It was a relatively close thing. It wasn`t something that we never felt that we had control of. But our interests are always the interests of public safety."
Rauf escaped from police custody in Pakistan in mysterious circumstances in 2007.
US officials said they believed they killed him in an attack with an unmanned drone last year but his death has never been confirmed.
The discovery of the plot in 2006 sparked chaos at airports, as authorities worldwide immediately introduced draconian regulations limiting the amount of liquids that passengers can carry on to flights.
Many of the rules remain in place.