Counter terrorist police were "a road away" from intercepting the Glasgow Airport bombers as they set off on their suicide mission.
Detectives chasing the on-the-run Islamic extremists were moments from preventing the terrifying car bomb attack on the airport terminal.
Police sources said officers reached the al-Qa'ida-inspired terror cell's bomb factory just moments after Bilal Abdulla and Kafeel Ahmed left on 30 June last year.
The address was traced after "urgent and frantic" examination of mobile phones found in two West End car bombs that failed to explode the previous day.
But the men had already left for Loch Lomond in a powerful four-wheel drive Jeep Cherokee hastily loaded with gas cylinders, petrol and nails.
The men spent eight hours at the beauty spot praying and preparing for a suicide attack as police continued their massive manhunt.
Officers traced them to the area of the loch but, armed only with poor quality CCTV images and no description of their vehicle, could not find them.
Meanwhile the semi-detached family home at Neuk Crescent, near Houston, was put under surveillance.
Hours later, after the airport attack, the front door was smashed down to reveal an astonishing hoard of bomb-making materials.
Officers discovered the conspirators planned a wave of car bombings with enough materials for at least two more devices.
One senior detective said: "We were literally a road away from them at the time they left for the next attack. That shows we very nearly got it right. We were very close to finding them at Neuk Crescent."
During the trial Abdulla said he joked "those guys are useless" as he and Ahmed were not stopped by police as they drove away from the bomb factory.
The discovery of two car bombs in the heart of London's West End the previous day caught counter terrorist police completely by surprise.
Officers were shocked to link four highly-educated professionals, including three NHS doctors, to the conspiracy.
The discovery prompted Prime Minister Gordon Brown to review health service recruitment and raised questions about the UK's dependence on foreign medics.
Abdulla was a junior doctor at the Royal Alexandra Hospital, Paisley, while Ahmed was an Indian PhD aeronautical engineering student.
Asha, a high-flying neurologist at the University Hospital of North Staffordshire, was also arrested.
He was acquitted of terrorist offences today at Woolwich Crown Court and is expected to return to Jordan.
Ahmed's brother Sabeel, then an NHS doctor working at hospitals in Warrington and Halton, Cheshire, was also held.
He admitted withholding information about the attacks from police earlier this year but was not involved in the plot.
Investigators said they were shocked to learn of the men's responsible, health sector backgrounds.
The detective added: "Just the whole idea of people who take the Hippocratic oath who then go on to wantonly seek to destroy human life in the most horrific way imaginable. That is what I find shocking, on a personal level, as well as a professional."
Police discovered Abdulla and Ahmed were driven by an intoxicating combination of jihadi rhetoric and rage at the suffering of fellow Muslims.
Abdulla joined militia fighters in Baghdad as the city descended into chaos following the 2003 invasion by coalition forces.
Ahmed, whose family live in Bangalore, was inspired by rebel fighters in disputed Kashmir and on fundamentalist websites.
In their wills, both Abdulla and Ahmed admitted acting on behalf of a mystery "emir" [leader].
Security services suspect Abdulla was sent to London by senior insurgent figures who saw his British passport as his greatest weapon.
They have not revealed if they traced any communications between Abdulla and other figures in Iraq since he first travelled here.
Nevertheless, just hours before the attacks, one chat room often used by al-Qa'ida supporters posted a prophetic message.
A frequent visitor to the al Hesbah website wrote: "Today I say: 'Rejoice, by Allah, London shall be bombed."'
The terrorists spent hours online meticulously researching improvised vehicle bombs using gas cylinders on Islamic extremist websites.
The Mercedes cars, packed with gas cylinders, petrol and nails, were modelled on improvised bombs deployed to deadly effect by insurgents in Iraq and Afghanistan.
One was left outside the entrance to Tiger, Tiger, a trendy night-spot in Haymarket, close to Piccadilly Circus, packed with 550 late-night revellers.
The second car, parked in adjoining Cockspur Street near a night bus stop, was designed to kill and maim those fleeing the first blast.
Two sophisticated mobile phone initiators, each showing up to four missed calls, were found in each vehicle.
The carefully-adapted phones were the centrepiece of the bombmakers' deadly plan to launch an extended bombing campaign across Britain.
But they gifted vital clues to police when the cars failed to explode through a combination of loose wiring and the smothering effects of the petrol and gas vapour.
Their final strategy bore chilling echoes of a series of previous al Qaida-inspired terrorist attacks.
Terrorist Dhiren Barot plotted to park limousines packed with gas cylinders and petrol in underground car parks.
The choice of nightclubs as targets was also reminiscent of the so-called fertiliser bomb gang led by Omar Khyam.
One member of his cell dreamed of slaughtering "slags" as they danced in a West End nightclub.
Police found evidence the cell considered targeting music festivals in Cambridge, Leeds and Manchester as well as Soho pubs and events in Cambridge.
Abdulla also wanted to launch the attacks on a significant date at the start of Mr Brown's term in Downing Street but it was delayed because he was so busy at work.
The police source added: "These men were intending to commit murder on an indiscriminate and wholesale scale.
"In addition to killing innocent members of the public, their objective was to seize publicity both here and abroad.
"We believe the defendants knew the public would be gripped by fear, not knowing when there would be another terrorist attack.
"If successful, we believe that many people would have died and been seriously injured, particularly young people who would have been enjoying themselves or on their way home after a night out.
"The repeated attempts to detonate the cars failed not through lack of effort, it was more a matter of luck than judgment that no one died that night."
One mystery that remains is whether the men recorded martyrdom videos for distribution on the internet.
Both Ahmed and Abdulla wrote wills intended to explain their actions to their families and other extremist followers.
Investigators discovered a badly-damaged video recorder in the shell of the burnt-out Jeep, but no tapes were found.