The bombers who struck London on Friday and are directly linked to the first terrorist attack in Scotland since Lockerbie are bound to have come from close to home. Almost all the recent terrorism plots exposed in Britain have involved young British citizens or immigrants who have spent a long time living in the UK.

The tactics have changed considerably since the July 7, 2005 attackers left the Beeston suburb of Leeds to kill themselves and 52 London commuters.

The latest bombers were not prepared to kill themselves, perhaps indicating a recognition within terrorist cells that footsoldiers are too valuable a commodity to be used in just one mission.

A lack of willingness to martyr themselves for the cause is also being read by terrorism experts as a sign that fanatics are being radicalised more quickly but less deeply than in the past. They have not had time to psychologically prepare themselves for a suicide mission.

Ed Husain, who joined a radical British Islamist group in the early 1990s, claims the process of recruiting home-grown terrorists by emphasising Muslim deaths abroad is well established.

"Their war was Iraq, ours was Bosnia, but it was the same ideology, the same us and them' mentality that drew them in," says Husain.

"The big difference is that when we were active in the mid-1990s, open jihadist mentality and suicide bombing took time to emerge. Now it's easier and quicker. Depending on the individual, they get radicalised in week one and they can get to the stage of physically taking action against those they oppose within 12 to 13 weeks."

There is a suspicion, shared by Gordon Brown's new international terrorism adviser, Lord Stevens, that British-born al-Qaeda operatives, have returned as veterans from Iraq to guide self-recruited terrorist groups here. That would explain how the gas cylinder car bombs common in Baghdad have turned up three times in two days on British streets.

The failed London bombs have left a valuable forensic trail for police to follow which may match the profile of suspects already known to them.

Police are also urgently trying to track down five dangerous terrorist suspects on the run from Home Office control orders. One of these men, Lamine Adam, 26, allegedly boasted of targeting nightclubs.

Misogyny is central to extreme Islamism, and so nightclubs, containing liberalised women who offend pious fundamentalists, are legitimate places for mass murder, as the bombings in Bali in 2002, which 202 people, demonstrated.

By Saturday morning, London, which was hosting a Gay Pride march and the Diana Memorial Concert, was saturated with police and not an easy environment for an active terrorist.

But if you were launching an attack in Scotland yesterday, Glasgow Airport would have been a good choice - most of the country's security resources would be concentrated on the Queen's state opening of parliament in Edinburgh.

There is now evidence that the London bombers were sufficiently familiar with Scotland to have stolen the metallic green Mercedes used in the attempt to bomb the Tiger Tiger club from the country. Police have traced the car's journey from this country to London and are trying to work out its movements beforehand.

If the terrorists took a car from Scotland to bomb London and then returned north to carry out a second attack, perhaps they had more than passing familiarity with the country. Scotland might yet turn out to have been the recruiting ground for an Islamist terrorist cell.

l I was a teenage fundamentalist: Seven Days