Police were just an hour behind bombers

At 1.47pm on Saturday June 30, 2007, Kafeel Ahmed sent a text message from his mobile phone to his brother in Liverpool. It took just seconds but it lit up the police hunt for the most wanted men in Britain.

Torcuil Crichton and Marianne Taylor

A mobile phone trail from the failed Tiger Tiger nightclub attack in London, barely 24 hours earlier, had already led anti-terrorist officers to Scotland.

An innocuous house in an ordinary street, 6 Neuk Crescent in Houston, Renfrewshire, had already been linked to the suspects. In the early hours of Saturday, police had arrived there and put the address under covert surveillance, not knowing the movements of the men who had rented the property. The suspects had left less than an hour before the police turned up.

As anti-terrorist officers scanned phone traffic for a trace of the terror cell, they knew they were just one step behind the fleeing bombers. When the text message intercept placed Ahmed's mobile somewhere around Loch Lomond, senior officers at Scotland Yard felt the net was closing.

In cities mobile cell coverage can narrow down to a few streets but in rural Scotland one mast can cover many acres - as is the case on Loch Lomond. Strathclyde Police, on high alert, immediately started patrolling along the A82, the main road along Loch Lomond's western banks.

The police were close but Kafeel Ahmed and his fellow bomber, Dr Bilal Abdulla, were in fact sitting at Milarrochy car park on the opposite shore of the loch in a Green Jeep Cherokee, looking out over the calm, grey water. Having left so much evidence intact in the failed Mercedes car bombs in London they knew that their luck would not hold and that, after the phone call was made, their time was short.

Barely 24 hours earlier, the fates had been cast the other way and hundreds of innocent people had escaped the first wave of carnage that Abdulla and Ahmed had tried to unleash on Britain.

The two men had escaped on rickshaw and then car from central London after failing to detonate two car bombs outside a crowded nightclub. They knew they had left clues that would lead the police directly to them so the men, one a doctor at the Royal Alexandra Hospital in Paisley, went to the lochside to prepare themselves for what was to be a final mission - a suicide attack that would bring vengeance for the fire and death of Iraq.

Ahmed's text message gave details of an e-mail explaining his reasons for seeking martyrdom, which for him would come a month later when he died from the wounds of his self-imollation. Having relayed his last testament the Indian engineer started the vehicle and headed back towards Glasgow. Within an hour the Jeep was driving down the offramp from the M8 motorway to Glasgow Airport. Kafeel drove straight for the passenger terminal doors. Islamist terrorism had come to Scotland.

Few who witnessed the carnage at the airport will ever feel complacent about terrorism again. A burning Jeep, packed with explosives, deliberately driven into the terminal building was aimed to cause maximum death and destruction. Only the hasty and haphazard execution of the suicide mission by the bombers spared Glasgow the horrific scenes of Madrid or London.

Both missions were bungled - the car bombs at Tiger Tiger in central London the night before failed to detonate because of faulty wiring in the detonation system, while the mixture of fuel and air in the sealed vehicles meant there was not enough oxygen to allow ignition. "It was a matter of luck, not judgment, that the bombs did not explode," said one of the senior investigating officers.

In a trial lasting eight weeks, the jury heard how the pair had driven two Mercedes cars, packed with gas canisters, petrol and nails, into London in the early hours of Friday June 29 in what was the culmination of months of planning.

Police believe the men were a self-motivated cell and not part of a wider terror plot. Although Abdulla is believed to have shown up on a security services' watch-list and may have taken part in the insurgency in Iraq, police found no evidence linking the men to other terror suspects. Abdulla and Ahmed met in Cambridge in 2004 where they also became friends with Mohammed Asha, the talented Jordanian neurologist who later moved to Staffordshire while the other two moved back and forth between Britain and their homelands. Dr Asha was cleared in court of all the charges he faced.

Ahmed, a 28-year-old engineer, arrived in the UK from India on May 5, where he was collected at Heathrow Airport by Abdulla, 29, who by then had a post as a diabetes specialist at Royal Alexandra Hospital. He rented the semi-detached house in Neuk Crescent, where, behind closed doors and drawn curtains, he and Ahmed set about creating a bomb factory.

Abdulla had spent weeks looking for the ideal property to rent. Ahmed had requested a garage and the pair were conscious not to draw attention to themselves. The three-bedroom house was a good size and was sited in a quiet road.

Bin liners were used to cover the garage window so Ahmed could work untroubled. Inside the house the living room was turned into a makeshift workshop where the circuitry was tested and the home-made initiators assembled.

When police broke into the house in the early hours of Sunday July 1, 2007, they found more than 1000 items including mobile phones, batteries, matches, syringes, light bulbs, soldering kits and diagrams of electrical circuits strewn over chairs and tables - everyday materials that, when wired together, had the power to set off car bombs remotely.

In the garage, the two men transformed family vehicles they bought from across the UK through the pages of Autotrader into deadly car bombs, the most successful weapon in the modern terrorist arsenal.

The two men had spent £3450 on five different cars, which would carry the home-made devices. When police stormed the Neuk Crescent bomb factory they found prepared kit ready to arm at least two more bombs.

They used false names for purchases and spread their spending across a wide geographical area so as not to arouse suspicion in the DIY stores that supplied most of their materials. Ahmed spent much of June travelling across Scotland and the north of England to buy the bomb components from different shops. If the two men went out together, they would enter and leave the shops separately and pay for items individually.

At the same time, they were buying jerry cans from petrol stations across the west of Scotland, filling them with fuel and searching the internet to find out how best to ignite them. The two men had viewed dramatic video clips on YouTube of gas canisters exploding, including one film entitled "very cool propane bomb". Abdulla provided his friend with a military electronics manual to create a simple circuit allowing the cars to be detonated remotely using mobile phones.

While Abdulla continued to work shifts at the Royal Alexandra Hospital, Ahmed worked to assemble the bombs using components bought from Halfords and B&Q stores.

Abdulla and Ahmed carried out reconnaissance of London in May 2007, using a hired Vauxhall Astra to tour its streets. They drank coffee in Starbucks and considered striking Buckingham Palace, 10 Downing Street and the Houses of Parliament in a wave of terrorist attacks to greet Gordon Brown into office after he succeeded Tony Blair. But the bombs were not ready and the work shift at hospital did not release Abdulla.

After realising the prime targets were too heavily guarded, Abdulla, the leader of the group, decided to strike at a symbol of what he saw as the decadence of the country of his birth - the city's hedonistic nightclub scene. He picked London's Tiger Tiger nightclub, in the heart of the capital's West End, as a symbol of Britain's free and open society.

In the speech being prepared for a martyrdom video, he wrote: "Do not blame us, but blame the shameless people who comprehend nothing in life apart from what relates to sex and alcoholic drinks.

"The truth is that these people do not care about what is happening in our land as they are all busy with alcoholic drinking and with their intimate friends.

"These people can only be awaken by the sound of booby traps and the Mujahideen hailing, God is great'."

The will Abdulla left behind on a laptop in the blazing Jeep was addressed not to family or friends, but to Osama bin Laden.

While they prepared car bombs, similar to those that had proved so deadly in the hands of insurgents in Iraq, the pair also tried to continue with their "normal lives" so as not to rouse suspicion and took time off from the plot to visit friends in Manchester and Lancaster. Abdulla spoke regularly to Dr Asha, 28, and made several visits to his home. Ahmed was in close contact with his brother Sabeel and also visited him in Liverpool, claiming to be back in Britain to do work on his PhD.

In the early hours of June 29 the pair drove in convoy into central London and parked one car outside the Tiger Tiger nightclub in Haymarket, which was full of young revellers, and the other in nearby Cockspur Street. They chose Mercedes cars to carry the devices because the marque is often used by illegal taxi drivers - so they thought they would not arouse suspicion in central London. This would buy them valuable time once they were parked outside a busy nightclub, enabling them to arm the detonators, exit and leave the vehicles for several minutes.

Hidden under duvets on in the passenger footwells were two 13kg gas tanks surrounded by hundreds of assorted nails.

Inside the boot were 10-litre or 25-litre containers filled with petrol. Fuel had also been spread around the passenger compartment of the car.

To detonate the bombs, Ahmed had built home-made initiators, which were linked via an electrical circuit to the buzzer unit of a mobile phone.

If the phone received a call it would complete the circuit and send current to the detonator - a light-bulb filament surrounded by broken match heads and packed inside a syringe. The filament was supposed to ignite the match heads and the petrol, causing the gas canisters to explode.

The nails scattered inside the car would have increased the chance of passers-by being killed or seriously injured and shrapnel could have been blasted up to half a mile from the scene.

There were two mobile phone detonators, each on a different network, in each car - but the devices failed because of a loose wire in the Tiger Tiger car which did not complete the electrical circuit and because the fumes and fuel forced out of the cars the essential ingredient for ignition - oxygen.

For the Glasgow suicide attack, Abdulla and Ahmed packed six gas canisters into the back of the Jeep. But they were grouped so tightly together that when fire did break out, the sides and bottoms of the containers were protected from the extreme heat and flames and did not explode despite determined efforts by Ahmed to set them, and himself, alight.

After several calls to the Mercedes detonators, it became clear Ahmed's engineering skills had let them down. The terrorists hoped their huge nail bombs would bring carnage in the West End but one of the cars had been booked for illegal parking by a zealous traffic warden and was actually lifted to be impounded. With both cars intact, and the records of two mobile phones from each of the vehicles, a massive police trawl of CCTV footage and phone traffic got under way.

The pair returned to their hotel, quickly realising the devices would leave a trail of clues that would lead police to them, then drove back to Houston, via Stoke, where they met up with Dr Asha on Friday evening. Late that night, they were back at Neuk Crescent and worked through the night preparing a third vehicle for the next attack.

The two blasts in the West End were to be the start of a campaign of bombings across the country, which, the men knew, would end in a suicide attack. The police also knew that they were in a race against time but they had no idea of how many were involved in the plot or where the bombers would strike next.

Senior police officers describe the next few hours as being reminiscent of a training exercise. After one challenge was overcome, another immediately cropped up. "Six Neuk Crescent was discovered very soon after it was vacated," said a police officer. "We then tried to establish a direction of travel," said a senior officer.

By Saturday afternoon, with Dr Asha under surveillance and a mobile phone trace on his phone the police were, not one street away, but one road away, albeit separated from their quarry by Loch Lomond. An hour later, officers received calls about an incident at Glasgow Airport.

At 3.12pm on Saturday June 30, the green Jeep Cherokee reached Caledonia Way in front of a Glasgow Airport terminal packed in the first weekend of the Scottish school holidays.

After skipping through the barrier behind a taxi, and Abdulla and Ahmed prepared themselves for martyrdom.

Seconds later, Ahmed turned the steering wheel towards the building and pressed his foot down on the accelerator.