The Director General of MI5 has issued a powerful defence of Britain's co-operation with intelligence agencies in America and other countries accused of the abuse and torture of detainees, saying they had stopped "many attacks" in the aftermath of the September 11 strikes.

Speaking for the first time about charges of MI5 complicity in the abuse of suspects overseas, Jonathan Evans said Britain had had to get overseas help at the time as its own knowledge of al-Qaeda was inadequate and the terrorist organisation might have hit again "imminently".

MI5 would have failed in its duty if it had not worked with its overseas connections to safeguard Britain, he said in a speech at Bristol University last night.

"Such intelligence was of the utmost importance to the safety and security of the UK," said Mr Evans. "It has saved British lives. Many attacks have been stopped as a result of effective international intelligence co-operation since 9/11," he said...

... He stressed that it was not "just a theoretical issue" as al-Qaeda had actually laid plans for further terrorist outrages in the wake of the attacks on the twin towers in New York...