Their crimes, should they have borne fruit, were easily capable of dwarfing the cataclysmic attacks of 9/11, and with evidence of direct links to Al Qaeda masterminds in Pakistan finally being made public the convictions leave little doubt that, eight years on, the threat is as real as ever.

Abdulla Ahmed Ali, Tanvir Hussain and Assad Sarwar were today found guilty of conspiring a crime so heinous it would have been almost unrivalled in recent history, killing upwards of 1,500 people and shattering the bubble of security that has subtly cloaked democratic civilisation since 2001.

It took two trials and £35 million of taxpayers' money, but the successful conviction of three men who plotted to blow up transatlantic jets has brutally driven home the ongoing terror threat facing the West.

The three British citizens were found guilty of conspiring to blow up seven separate planes - all scheduled to depart from London Heathrow and bound for various destinations in North America in August 2006.

Only now have full details of their ingenious liquid devices been released. Experts insist that contemporary security measures would not have been able to detect the small and masterfully concealed bombs, which according to a reconstruction staged by the Crown Prosecution Service and reenacted by the BBC were easily capable of downing the jets.

Click here for footage of mock-up devices being detonated

"This stood out as being of a very substantial dimension, advanced, specific and sophisticated and of a scale comparable to 9/11," US former homeland security chief, Michael Chertoff, sternly told The Guardian.

The terrorists had planned to conceal liquid explosives within drinks by drilling holes in the bottom of bottles - the contents of which were then to be replaced a hydrogen peroxide-based mixture, dyed to mimic the colour of the drinks, before being resealed in the unopened containers.

The highly unstable chemicals would then have been detonated mid-flight by suicide bombers, rupturing the fuselages of the commercial airlines and killing all those onboard as well as untold numbers on the ground.

In the aftermath of the 2006 arrests, airports were thrown into chaos as security alerts rippled around the globe about the hitherto unseen vulnerability. All containers exceeding 100ml were immediately banned from hand luggage within Europe and America – a measure that remains in place today.

But securing convictions against the terror plotters proved unexpectedly difficult. A lengthy retrial became necessary after the first jury found the three ringleaders guilty only of the lesser charge of conspiracy to murder, failing to conclusively prove the full scope of their plans.

It was ultimately records of coded emails sent by the three British terrorists to their Pakistan-based Al Qaeda backers, coupled with hours of surveillance footage and circumstantial evidence, which sealed their fate.

Click here to read the trail of emails between the UK and Pakistan

The primary recipient of these emails was Richard Rauf, a British man from Birmingham who relocated to Pakistan and was known to have established direct ties with the Al Qaeda leadership there. Indeed it was his arrest in 2006 which expedited the swoop on the British terrorists' home, with Scotland Yard fearing that the suspects could learn of his fate.

Mr Rauf subsequently fled Pakistani custody in an elaborate escape in 2007 - described by authorities as "mysterious" at the time - though it is believed that he was assassinated in a US drone attack one year later.

While the precise role he played in overseeing the foiled airliner plot may never be proven, separate evidence has emerged that Mr Rauf was one of the key players in the 7/7 bombings of 2005. MI5 and MI6 last year jointly wrote to Parliament's Intelligence and Security Committee warning that they believed he was a significant "facilitator" of the deadly attacks.

In America, there is little doubt as to his involvement in the transatlantic plot. "Rauf was the link between the plotters and the Al Qaeda end," Mr Chertoff said. "We know there was a connection to Al Qaeda central."

It is an inevitable reality that in plots of this nature questions will remain unanswered about the specific machinations deployed by Osama bin Laden's seditious and ever-more innovative web of global conspirators.

But with the latest convictions by an independently minded jury of our peers, there can be little doubt as to the potency of the dangers facing us.

"This case reaffirms that we face a real and serious threat from terrorism," a relieved Alan Johnson, the Home Secretary, said after hearing today's news. "I cannot thank enough those involved for their professionalism and dedication in thwarting this attack, and saving thousands of lives."