Smash hit

The director of Egypt's National Research Centre - which has sponsored Mr el-Nasher's studies in Leeds - told the Associated Press that the chemist had been acting quite normally since returning to Cairo, but had gone on holiday a week ago.

Dr Hany el-Nazer said: "It is difficult to believe such things. He came back to the NRC and presented his papers. I asked colleagues if they noticed anything strange about him and they said he was behaving normally during the last week before he took holidays."

It also emerged tonight that Mohammad Sidique Khan, who was responsible for the Edgware Road blast, was the guest of a Labour MP at the House of Commons last year. Khan visited Parliament in July 2004 in his capacity as a learning mentor at Hillside Primary School in Leeds. The bomber met Jon Trickett MP, whose wife is the headteacher at Hillside.

The four bombers, three of them from Leeds, have all now been named, either officially or unofficially. Police yesterday released a CCTV image of 18-year-old Hasib Hussain, who blew himself up and killed 13 others on the No 30 bus in Tavistock Square.

Detectives are trying to establish how Hussain spent the final 81 minutes of his life, after his bomb did not go off simultaneously with the other three. Police are anxious to discover if he may somehow have been unable to blow up a Tube train and sought last-minute orders changing his target to the bus.

By the time Hussain died, his two friends from West Yorkshire, cricketer Shehzad Tanweer and teacher Mohammad Sidique Khan, had been dead for over an hour.

Officers were also questioning the pregnant wife of Germaine Lindsay, a 19-year-old Jamaican-born man thought to have been the fourth bomber, responsible for the blast on the Piccadilly line between King's Cross and Russell Square which claimed 26 lives. Searches are continuing at the Lindsays' rented home in Aylesbury, Buckinghamshire, while police in Leeds today raided an Islamic bookshop near the home of Mr Tanweer.

Detectives also revealed that a suspected al-Qaeda operative entered Britain via a channel port two weeks before the attack. Although his name was on a security watch list he was not put under surveillance, as he was not regarded as being of sufficiently high risk. He is believed to have left the country hours before the attacks.

Intelligence leads suggest that the four British bombers were approached by the mastermind of the attacks, a British Pakistani Muslim, while they were abroad.

Sir Ian Blair, the Metropolitan Police commissioner, warned today that the death of the four young men involved in last week's attacks had not lowered the threat of a subsequent atrocity. A second attack was highly probable, he said.

But he said that the carnage presented an opportunity for the Muslim community to become more closely engaged in the war on terror, and suggested that mosques could set up their own terrorist hotlines.

He said: "What we expect to find at some stage is that there is a clear al-Qaeda link. The four men who are dead are in the category of foot soldiers, what we've got to find is who encouraged them, who trained them and who is the chemist?

"I don't think [the death of the bombers] makes a future attack any less likely."

The Commissioner told faith leaders in Romford that he relied on them to become involved in rooting out the dangerous elements in their midst. "Now is the moment when all communities come together and move into active engagement in counter-terrorism.

"Police and intelligence agencies won't defeat terrorism - communities will. There's an issue within the Muslim community about the really lunatic fringe of preachers; that they have said they don't need to worry about them. Unfortunately we do need to worry about then. We need to know who the young men are who are preaching outside mosques rather than inside them.

"This is a sea change. Out of tragedy comes hope. I'm going to be meeting with a series of senior Muslim leaders this weekend and we will work a way through in which they provide information. Let's say they operate their own third party reporting, they set up their own terrorist hotline, these are the kind of things we can do.

"I'm absolutely positive we will break this, we will break this horror that has descended on us."

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