In Madrid, the team were all of North African origin. For September 11, Osama bin Laden chose almost all Saudis. The suicide bombers in Istanbul, whose targets included the British Consulate, were all ethnic Kurds, from the same city in southeast Turkey.

Organisers normally prefer to recruit from the same communities, so that their cells have a common language, a shared cause and can often be drawn from the same neighbourhoods.

What distinguishes the British cells of suicide bombers is the striking differences between their family backgrounds, their upbringings and even their pastimes.

Detectives have been piecing together these eight lives to determine how their paths crossed. The suspicion is that these fanatics from north and south met at Finsbury Park mosque.

Mohammad Siddique Khan, 30, the oldest of the Leeds bombers and the suspected leader of that group, is known to have visited this North London mosque over recent years. Police are investigating claims that a second Leeds bomber also spent time there.

The East African-born cell lived not far away in North London, so this was a regular place of worship.

Other would-be suicide bombers linked to the mosque include Richard Reid, who tried to blow up a passenger jet in midair, and Zacarias Moussaoui, the so-called 19th hijacker from the 9/11 attacks.

It was also a focal point for European and American converts to Islam, including a number linked to terror cells.

While police are still trying to establish where these eight men have travelled and whether they attended madrassas or foreign training camps, the belief is that the first moves to turn them into jihadis probably happened here.

Properly known as the North London Central Mosque, the five-storey redbrick building was taken over by a group of Islamist extremists in the mid-1990s.

Situated close to Arsenal FC’s Highbury stadium, it subsequently became a centre for radical activity and the commonly associated criminal enterprises of credit card fraud and identity document forgery. These activities have stopped since the mosque has come under new leadership.

Not all those attending the mosque, which was built in 1988, were extremists or terrorist sympathisers. Many members of the local Muslim community attended it as their nearest place of worship.

But the radical takeover made the mosque an immediate draw for Algerians arriving in London as refugees from bitter conflict in their homeland. Among those genuinely fleeing the massacres in Algeria were members of the GIA and GSPC terrorist groups.

For many refugees, Finsbury Park mosque was a place where they could buy forged or stolen passports and identity documents that would enable them to find work. It was also a place where they could buy clothes, which had often been stolen by gangs of shoplifters.

Refugees from the conflict in Somalia also gravitated towards this area of North London and the mosque, which was the focal point of its Muslim community.

The mosque offered the displaced not only a place to pray but also a place to sleep. Over the years thousands of people are thought to have used the basement as a dormitory. Immigration authorities often wrote to people care of the mosque.

Those who made the mosque the centre of their lives became prey for the radical preachers and activists. They held regular prayer groups, study circles and political lectures at which their brand of fundamentalist Islam was preached in violent, uncompromising terms.

The Taleban regime in Afghanistan was held up as an example of how to run an Islamic state and money was raised to send people and equipment to Kabul.

Youths from the Pakistani and Bangladeshi communities went there, as did a number of black African Muslims and black British converts to Islam.

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