A leaked “top secret” document published in The Sunday Times yesterday indicated that there was intelligence on one of the July 21 suspected bombers. One of them was reported to have been subjected to a short-term intelligence operation. It has already been admitted that MI5 had two of the July 7 bombers under surveillance a year before the suicide attacks in London that killed 52 people last year. Neither of the two, Mohammad Sidique Khan and Shehzad Tanweer, was judged to be a serious threat at that stage, and MI5 felt that it was unjustified to commit extensive resources to a lengthy surveillance operation.

MI5 and MI6 have been giving evidence to the parliamentary Intelligence and Security Committee (ISC), which is investigating the secret material available in the lead-up to the July 7 bombings. The ICS report is due in April.

After the leak yesterday of an intelligence document that included comments from the head of MI6 about the July 21 failed attack, security forces were adamant that there had not been “an intelligence failure” before the London incidents. John Scarlett, the chief of the Secret Intelligence Service (MI6), is quoted in the document as saying that MI5 had asked his agency to check on a suspect known to be visiting Pakistan. The suspect later featured in the investigation begun after the July 21 incident. According to the document it was a “low-level” investigation and nothing came of it.

The leaked material is believed to be part of an intelligence report drawn up by the Joint Terrorist Analysis Centre (JTAC) an MI5-based organisation that is represented by all the secret agencies and the Metropolitan Police, the military and government departments.

The JTAC, which monitors and analyses all secret intelligence material relating to the terrorist threat to the UK and British interests abroad, has been collating all material linked in any way to the July 7 and July 21 incidents.

Four suspects have been charged in connection with the July 21 failed attack.

One security source said: “The Security Service (MI5) stands by intelligence decisions it made in 2004. They were based on an analysis of the individual risks at the time and the resources available.” The source rejected a suggestion in the Sunday Times article that dissident MI5 officers had leaked the document.

The source added: “We have to decide if individuals pose a credible and immediate threat. If they do, we put everything we’ve got into investigating them. If they don’t, there are plenty of others who do.”

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