Today's report by MPs into the July 7 bombings reveals the scraps of evidence that were known by the security services about three of the four bombers, but lost and sidelined as analysts concentrated on known attempts to attack the UK.

The report says the decision to drop investigations into Mohammad Sidique Khan and Shehzad Tanweer, two of the attackers, was understandable at the time, but shows the fragments of information that might have been used to unravel the plot.

Mohammad Sidique Khan and Shehzad Tanweer

Khan, the leader of the bombers, and Tanweer were among "a number of unidentified men" at meetings under the surveillance of MI5 in early 2004 as part of a separate "important and substantial" investigation. Khan's phone number had already turned up in a separate MI5 operation in 2003.

"Intelligence at the time suggested that their focus was training and insurgency operations in Pakistan and schemes to defraud financial institutions. As such, there was no reason to divert resources away from other higher priorities, which included investigations into attack planning against the UK," the report said.

Surveillance of Khan and Tanweer that might have led to their identification started but then stopped, according to the report, because they were not thought to be either "essential" or "desirable" sources of information.

After the bombings, Khan was linked to evidence given by a security detainee a year earlier when another prisoner recognised him from a press photograph. The evidence revealed that Khan had visited Pakistan in 2003 and subsequently with Tanweer from November 2004 to February 2005. A subsequent report given to MI5 in early 2005 also described Khan's movements, but no link was made.

Today's report said that if Khan, whose identity was masked by a series of pseudonyms, had been recognised earlier, "it is possible that the Security Service might have allocated more effort to identifying and investigating him prior to July".

Germaine Lindsay

A telephone number belonging to Lindsay, the 19-year-old Jamaican-born convert to Islam who killed 26 people in the Russell Square explosion, was found in the files of MI5 after the atrocity. But "it was only possible to identify [the number] after the attacks", according to the report.

Hasib Hussein

The youngest bomber, a friend of Tanweer's who played football at the community project run by Khan, was on the only one of the four attackers completely unknown to the security services. Hussein, 18, blew up the bus in Tavistock Square, killing 13 people.

The Pakistani link?

Today's report dismissed the idea that the bombings were organised by a specific mastermind who left the country just before the attacks but it admitted that the bombers were in regular and secretive contact with Pakistan in the run-up to July.

"Contacts with Pakistan in the run-up to the attacks suggest advice or direction may have been provided from individuals there," said the ISC report. The Home Office narrative released this afternoon made the same point, stating:

"Between April and July 2005, the group was in contact with an individual or individuals in Pakistan. It is not known who this was or the content of the contacts but the methods used, designed to make it difficult to identify the individual, make the contacts look suspicious."

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