Bombers begin the journey to murder.

A chilling picture of the suicide bomb squad which killed 55 people in London has been released.

The four were captured on CCTV strolling into Luton station en-route to the capital.

Each carries a rucksack packed with explosives to be detonated on three Tube trains and a bus.

The picture was released by officers hunting the terrorist support team believed to be behind the outrage amid reports that MI5 missed the chance to stop one of the men.

Mohammad Sidique Khan, the Edgware Road bomber, was apparently assessed last year when his name came up in connection with another alleged bomb plot.

But officers failed to place him under surveillance after deciding he posed no risk.

Like hundreds of others linked to the inquiry, he was judged to be "on the periphery" of the suspect's cell network, an unnamed government official was reported as saying.

However, there was nothing to suggest his murderous intent as he was captured on CCTV with fellow suicide bombers Hasib Mir Hussian, 18, of Holbeck, Leeds, and Shezad Tanweer, 22, of Beeston, Leeds and Jamaican-born Germaine Lindsay, of Buckinghamshire.

A married man with a baby girl and another child thought to be on the way, his family yesterday suggested he had been "brainwashed" into carrying out the "evil" attack.

Relatives called on anyone with information to "expose these terror networks which target and groom our sons", in a statement issued through police.

Lindsay's wife, Samantha Lewthwaite, said in a separate statement that she was "horrified by the atrocities". Hussian's family has also condemned the attack.

Tony Blair repeated his call yesterday for the country to stand together in the face of the attacks.

"It is not a clash of civilisations ( all civilised people, Muslim or other, feel revulsion at it," the Prime Minister said during a speech in London.