The terrorists responsible for the Tube and bus attacks in London have been revealed as home-grown suicide bombers. The four young British men, all thought to be of Pakistani origin, are believed to have blown themselves up with rucksack bombs on Thursday, killing at least 52 people. Three of the bodies of the terrorists responsible for what was the first suicide bombing in western Europe have been identified, while a fourth is thought to be among the remains in the wreckage on the Piccadilly line between King's Cross and Russell Square. Police raids at six homes in north Yorkshire yesterday also led to one arrest. But senior security sources warned last night that they suspected al-Qa'ida planners ­ bomb-makers and organisers ­ were still at large and further suicide bombings were likely. The four men, including one teenager, all from Leeds and Dewsbury in West Yorkshire, were not considered Islamic extremists and were not thought to have significant links with terrorism. The realisation that British nationals are prepared to make suicide attacks has transformed the way the country will have to view security.

Britain and the US are privately planning to withdraw most of their forces from Iraq by early next year, according to a secret memo written by John Reid, the UK defence secretary. Under the plans, Britain will cut the number of its troops from the present 8,500 to 3,000 by the middle of next year. The US will reduce its forces in Iraq from about 176,000 today to 66,000 by early next year. The plans, outlined in a document put to a cabinet committee chaired by Tony Blair, were revealed as the insurgency in Iraq claimed up to 40 lives and wounded dozens from suicide bombs in Baghdad, the Sunni Triangle and along the Syrian border. The surge of bombings followed a lull over the last week and took the toll of Iraqis killed since the new government took office on April 28 past the 1,500 mark. Mr Reid's memo, Options for Future UK Force Posture in Iraq, marked "Secret - UK eyes only", was leaked to the Mail on Sunday. It confirms a Guardian report last week outlining the views of British military commanders. Mr Reid says any final decision on force levels would depend on the security situation in Iraq, the state of the Iraqi security forces, and "internal Iraqi pressure". However, he reveals that the Pentagon is pushing for early and deep cuts in the number of American troops in Iraq, despite the concerns of US commanders in the field.