We have 'conclusive evidence' that Edward Snowden leaks hurt UK national security, say spy chiefs



Ministers have been given dossier on how GCHQ's work has been hindered

A senior official said this was 'unambiguous' evidence



Ministers have been handed ‘conclusive evidence’ of how leaks by surveillance whistleblower Edward Snowden damaged national security.



It claims suspected terror cells and individuals disappeared from the intelligence radar after the American revealed information on techniques used by the British listening station GCHQ.



A dossier showing how the publication of leaked material in newspapers including The Guardian affected UK spying operations has now been passed to David Cameron and senior Cabinet colleagues.

Spy chiefs claim that the work of GCHQ, pictured, has been severely compromised by Snowden's leaks

A senior counter-terrorism official yesterday said there was ‘unambiguous’ evidence that the release of information from the Snowden documents had made gathering information about terrorists more difficult.



Charles Farr, head of the Office for Security and Counter-Terrorism, told The Times: ‘Ministers want to understand the impact of Snowden and have been provided with material on more than one occasion.



‘It is part of our job to provide to ministers evidence that Snowden has changed our national security work.



‘I’m clear that that evidence is conclusive. Our coverage of counter-terrorist activity is not as good as it otherwise might have been.’



Edwards Snowden, the American whistleblower, has released classified documents

Mr Farr, among those tipped to take over as director of GCHQ from Sir Iain Lobban, refused to give specific examples of the damage done because it could create ‘a danger of making a problem worse’.



His comments come days after a watchdog rubbished claims about the extent of mass surveillance made by Snowden, 30, a former IT contractor with the US National Security Agency.



He stole tens of thousands of confidential and top secret files and leaked them to The Guardian and the Washington Post and has now sought refuge in Russia, where he was granted asylum.



However, the Interception of Communications Commissioner Sir Anthony May said it was untrue that MI5, MI6 and GCHQ, were engaged in ‘mass intrusion’ into the private lives of millions of innocent citizens.



Nor were they breaking the law, or using US intercept material to snoop on Britons overseas.

He said they did not ‘misuse’ the powers given to them by Parliament to engage in ‘random mass intrusion in to the private lives of law-abiding citizens’. Such acts are not permitted by law and would be ‘comprehensively unlawful’, he added.



Mr Farr also revealed how terrorist suspects have been hauled from aircraft as a result of a new early warning system designed to give airlines better information about passengers.



He said a ‘handful’ of people judged to ‘pose a threat to aviation security’ have been stopped travelling by air as a result of work by the National Border Targeting Centre.

