This casually dressed bomber and the three others involved in Thursday’s botched attacks had not run to save their own skins; they wanted to live only so that they could strike again.

These four would not have cared that police had plenty of pictures of them from CCTV cameras and descriptions by witnesses as they hadn’t expected to survive. Now they had, the terrorists knew that they did not have long to make their move.

They could not lie low until London dropped its guard as there were enough clues to their identities and addresses left in a couple of the rucksacks abandoned on a Tube train and the No 26 bus to lead police to them and their families.

Just like the July 7 bombers, this group had carried documents and letters as they wanted the authorities to know this was another home-grown suicide team. This group appears to be from London.

Whoever orchestrated this operation appears to have used the “away day” team from Leeds for the first strike, leaving locals who knew their way around the capital for the follow-up mission. While the priority was to find the four, detectives also had to establish why Thursday’s effort had failed so spectacularly.

The suspicion is that the London cell had been deprived of some of the equipment and explosive abandoned in the boot of the car at Luton railway station after the July 7 attack.

Whoever constructed the devices for Thursday’s assault had to improvise with home-made detonators and appears to have made the same, simple mistake in all four bombs.

What was left behind in the rucksacks would allow experts to establish if this was the same cell. First indications are that it is.

Again, this cell does not care whether police have discovered the link with July 7. If anything, it suits their cause.

The events of the past 15 days have demonstrated there are at least eight men ready to sacrifice their lives. Police concede they don’t know how many more might be at large.

The terrorists have paralysed London three times in just over a fortnight, and if people are having second thoughts about visiting the capital this weekend then that also is part of their design.

A question remains whether all eight men ever met to co-ordinate their moves. The few arrests made so far may provide the answer but usually Islamic militant cells are taught to operate in isolation.

Late into Thursday night detectives sat with psychologists and others trying to fathom the mindset of the surviving bombers after their very public failure and how they would retaliate.

There was concern over whether to issue photographs of the men immediately, for fear it might spook the suspects into detonating what explosive they had left.

When the Madrid train bombers were cornered in an apartment they blew themselves up, killing one of Spain’s top anti-terrorist officers.

Undercover police were staking out addresses at first light yesterday and it was from one of those, it is understood, the young man emerged who was shot dead at Stockwell Tube station at 10am.

This group’s hope is that if these attacks continue on Tube and bus for many more weeks then the public’s resilience will begin to crack. These radicals want communities to turn on one another, and to condemn their politicians and police for their failure to eradicate this menace.

Senior officers knew the risks of instructing its armed officers to shoot to kill if they believe that a suicide bomber is about to strike. They realised that passers-by and travellers could get caught up in a gunfight or witness distressing scenes as Tube passengers did at Stockwell. They accept that highly trained firearms officers might shoot the wrong man.

Last night senior Scotland Yard officers were certain that their men did the right thing at Stockwell. The victim’s behaviour, the way that he was dressed, his refusal to stop when challenged by armed police and his determination to get to the platform meant that the undercover team had no option but to open fire.

Explore UK News

• Crime News

• Education News

• Health News

• Science News

• Scotland News

Times Recommends

• Forces chief faces new battle - the economy
• Seven days that shook the world
• Icelanders wake up and smell ... the fish