DAVID Cameron has come out in support of the head of MI5's warning that the ability of terrorists to attack Britain has been enhanced by the leak of the GCHQ files.

Asked whether the Prime Minister agreed with Andrew Parker's remarks, his spokesman said Mr Cameron thought his speech was "excellent".

When asked in particular if he thought the leaks from former CIA worker Edward Snowden, published in The Guardian, had been a help to terrorists, he replied: "I would point you to all parts of the Director General's speech, including that."

In his speech to the Royal United Services Institute, the MI5 chief criticised the newspaper's decision to publish the leaked classified material, saying they had caused "enormous damage" and had handed a "gift" to terrorists intent on attacking Britain.

However in response, Alan Rusbridger, the editor of The Guardian, defended his newspaper's role, claiming that it was stepping in where politicians had failed.

Challenged on Mr Parker's suggestions that publishing the information was helping terrorists, Mr Rusbridger replied: "They will always say that. You read histories of intelligence and you go back to the 1990s and the security people were saying the same."