By Chris Summers and Dominic Casciani
BBC News home affairs
Five men have been convicted of plotting to build a bomb which police say could have killed hundreds of British people. The men were caught after police and MI5 launched a massive surveillance operation.
Police swooped on the plotters in March 2004
While it was never going to be as devastating as 9/11, the British plot to build a massive bomb from fertiliser could have resulted in hundreds of deaths, say police.
Smashed three weeks after the 2004 Madrid bombings, in which 191 people were killed, the bomb plot was the British security services' first significant success against a rapidly developing threat from al-Qaeda sympathisers - but also a terrible indication of what was to follow in the London suicide bombings of the following year.
This was a plot devised by British men over a number of years as they travelled down the path of extremism. While the plot was stopped in its tracks, some of the conspirators wanted to bring a similar level of destruction to Britain as to that seen in Spain.
The al-Qaeda sympathisers, led by Crawley man Omar Khyam, began planning their attack in earnest in 2003.
Omar Khyam, 26, from Crawley, West Sussex
Anthony Garcia, 24, from Barkingside, east London
Jawad Akbar, 23, from Crawley
Waheed Mahmood, 34, from Crawley
Salahuddin Amin, 31, from Luton, Bedfordshire
Another two men, Nabeel Hussain and Shujah Mahmood, were found not guilty
Four of the men were from Pakistani family backgrounds - and it was meetings in Britain over the conflict in Kashmir, a key issue for many Muslims, that led the men to become interested in the mujahideen fighters in the disputed region.
Some of the men were involved during this time with al-Muhajiroun, the now banned Islamist group formerly headed by self-styled cleric Omar Bakri Mohammed.
In time, each of the men travelled to Pakistan to support jihadi groups and their armed campaigns. But the jihad was no longer just Kashmir - it was Afghanistan too.
British and American troops had invaded Afghanistan intent on capturing Osama Bin Laden and ousting his Taleban protectors in the wake of the 9/11 attacks.
Frustrated with being unable to go to the frontline, and angry over the 2003 invasion of Iraq, they decided that they should bring violence to the streets of the UK.
They agreed that Britain, which had supported the US in Afghanistan, did not deserve to remain unscathed for what they believed was a war against Muslims.
To carry out such an attack, they needed military skills. Khyam had already received some training with Kashmiri fighters. And in July 2003 he helped to organise a special secret training camp where some of the group learnt weapons and explosives skills.
A successful experiment with a small explosive device, comprising 1.5kg of ammonium nitrate fertiliser, convinced the group that a larger device could be used back in Britain.
Fertiliser has long been a key bomb ingredient used by paramilitary militants groups around the world, including the IRA.
Plot in the UK
The plotters returned to Britain and mulled over several ideas - one of which was to poison the beer at a football stadium. Another proposed targets included trains, pubs or nightclubs in Britain.
Internet cafe: Used to securely exchange plans
They discussed attacking the Bluewater shopping centre in Kent, the Ministry of Sound nightclub in south London and even the National Grid to maximise economic damage.
In November 2003 the group bought 600kg of ammonium nitrate, which was stored at a self-storage unit in Hanwell, west London. On the other side of the Atlantic, another alleged conspirator was designing a remote-control detonator.
But staff at the depot became suspicious and alerted the police. MI5 had already been taking an interest in Khyam because of his suspected links to a key al-Qaeda sympathiser working in both Britain and Pakistan. But it was the call from the storage unit that provided the evidence.
Undercover police officers replaced the ammonium nitrate with an identical, but harmless, substance. Bugging devices were placed in several of the defendants' homes and at least one car.
Police move in
In late March the security services decided to move in, partly because Khyam had mentioned to staff at Access that he would not need the storage facility after the end of March. Bugged conversations revealed Khyam and others revelling in the destruction caused by the Madrid attacks days earlier.
On 29 March they arranged for Khawaja to be picked up in Ottawa, Canada and within hours they swooped on the British end. He is awaiting trial.
The gang discussed the possibility of poisoning the beer at a stadium
Around 700 police officers from five forces were involved in a series of raids and six of the seven defendants were arrested.
Amin was later detained by the Pakistani authorities and was sent back to Britain a year later, where he was arrested.
But Babar had by this time left Pakistan and was picked up only later in the United States.
He pleaded guilty to conspiring to provide material support to al-Qaeda and has not yet been sentenced. But crucially, he agreed to give evidence against the other conspirators - the first major supergrass in a jihadi terrorism plot.