GCHQ did not break British laws in the use of the American Prism system to gather information, the Commons intelligence and security committee reported today. But the MPs also stated they would be reviewing the legislations regarding the effect of surveillance on privacy and human rights.

The Committee stated that, contrary to some claims, GCHQ had not circumvented regulations but instead sought information from the National Security Agency in the US only after a warrant signed by a minister had been in place on each occasion as required under the law..

MPs had interviewed the director of the government listening post, Sir Iain Lobban " in detail" and had also travelled to the US to meet officials of the National Security Agency (NSA) and their Congressional counterparts in their inquiry.

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Documents examined by the Intelligence and Security Committee (ISC) had included details of counter-terrorist operations in which GCHQ had sought and obtained intelligence from the US, a list of UK citizens and residents who had been subjected to monitoring as a result of the liaison and lists of mediums, such as e-mails, which were intercepted.

The ISC said in its report: "It has been alleged that GCHQ circumvented UK law by using the NSA's Prism programme to access the content of private communications. From the evidence we have seen, we have concluded that this is unfounded."

However, the Committee, chaired by former foreign secretary Sir Malcolm Rifkind, added: "it is proper to consider whether the current statutory framework governing access to private communications remains adequate". It was "examining the complex interaction between the Intelligence Services Act, the Human Rights Act and the Regulation of Investigatory Powers Act [Ripa], and the policies and procedures that underpin them, further."

William Hague, the foreign secretary, said in a statement welcoming the ISC report."I see daily evidence of the integrity and high standards of the men and women of GCHQ. The ISC's findings are further testament to their professionalism and values".

The controversy over wideranging interception by GCHQ of communications came as the independent reviewer of terrorism legislation, David Anderson QC, said the pattern of recent plots did not involve large networks, but small groups and, often, individual 'lone wolves'.

"The will and capacity to commit 7/7 style atrocities still exist in the United Kingdom, as demonstrated recently by the,

Birmingham rucksack bomb plot. However the bombers' chances of success have diminished with the marked improvement in MI5's coverage since 2005," he said in his annual report.

"Simpler attacks, involving fewer people and less planning, are becoming more common - including against national security targets, as in Northern Ireland - and can be very difficult to detect."

The lethality of such small-scale attacks was underlined by the killing of Fusilier Lee Rigby who was stabbed to death outside Woolwich Barracks in south east London in May. Security officials cast doubts at the time on whether telephone intercepts would have necessarily stopped the killing.Two men have been charged with the soldier's murder.

Mr Anderson had said in an interview earlier today: "We are certainly not seeing now what we saw in the years around 2005, 2006, which are the large, ambitious, 9/11-style plots perhaps to bring down simultaneously several airliners. What we are seeing is a trend towards lone actors and we are also seeing self-organised plots."