Another report will exonerate the security services, saying that they had no intelligence on the planned attacks, the Times said.

Four suicide bombs on three Tube trains and a bus killed 52 people and injured nearly 700 on July 7 last year.

The London blasts: complete coverage

'The Parliamentary Intelligence and Security Committee will today clear MI5 (Britain's domestic spy service) even though it had given no prior warning of an imminent attack. A separate narrative of the July 7 attack, written by the Home Office, backs the same line, with its 35-page account concluding that there is no evidence of a Mr Big masterminding the plot. The eight MPs and one peer on the ISC say that the four terrorists involved were home-grown but influenced by Osama bin Laden's war against the West,' the Times said.

'The report by the cross-party committee investigating the intelligence failure to stop the attacks is expected to blame it on a lack of resources rather than on any error of judgment,' said the BBC.

'Any failing, according to the reports, is a failure of resources rather than a failure of judgment, which will come as a relief for people in MI5, the security services,' said the BBC News security correspondent Frank Gardner.

The committee, which interviewed police and members of the intelligence community, is expected to ask why the lead bomber was not fully investigated despite being known to security officials, the BBC said.

But the government is likely to resist calls for a public inquiry on the grounds that the bombings were still part of an open murder investigation.

Following the release of the reports, "there is a risk that some people will call this a whitewash and I'm sure there will be increased demands for a public inquiry," the BBC quoted Gardner as saying.