MI6 thwarted bomb plot by Gaddafi’s henchmen

They were able to warn the National Transitional Council in Benghazi of the danger after discovering details of the planned attack by Muammar Gaddafi’s former regime.

Mr Hague said the agencies – which include the Secret Intelligence Service, MI6, and the electronic “listening” agency GCHQ – played a key role in the conflict which brought Gaddafi’s 42-year dictatorship to an end.

“They worked to identify key political figures, develop contacts with the emerging opposition and provide political and military intelligence,” he said. “Most importantly, they saved lives.

“For example the Gaddafi regime tried to attack the National Transitional Council in Benghazi, and to kill some of the Western representatives in Libya. The agencies obtained firm intelligence, were able to warn the NTC of the threat, and the attacks were prevented.”

It is understood this referred to planned suicide and car bomb attacks organised by Gaddafi’s security chief Abdullah al-Senussi targeting the NTC and foreign diplomats which were uncovered by MI6 in the spring.

Benghazi was the scene of an earlier debacle when SAS soldiers and an MI6 officer were covertly dropped into Libya to make contact with the rebels, only to be arrested by the people they were supposed to be helping.

Mr Hague was delivering a rare public speech on the work of the intelligence agencies, which he described “vital assets” with a “fundamental and indispensable role” in keeping the nation safe.

The disclosure of the agencies’ involvement in Libya comes amid criticism that MI6 had been too close to the former Gaddafi regime and was involved in the extraordinary rendition of anti-Gaddafi activists.

Speaking at the Foreign Office, Mr Hague acknowledged Britain’s standing had been damaged by allegations MI5 and MI6 officers had been complicit in the extradition and torture of terrorist suspects.

But while he said the Government was determined to tackle the issue, he strongly defended controversial proposals for secret court hearings in civil cases involving evidence of sensitive intelligence material.

“A blend of people, technology and partnerships give us an intelligence edge.

“If our techniques come to light, adversaries benefit and are able to switch techniques and communications resulting in a loss of knowledge about their plans,” he said.

“Many agents and sources risk their lives – some lose their lives – to give us the vital information to keep us safe. We have a duty to protect them.”

The Government drew up plans for closed hearings following a series of multi-million pound compensation awards made to former Guantanamo Bay detainees.