British intelligence chiefs believe that the CIA was hoodwinked by Iran.

British spy chiefs have grave doubts that Iran has mothballed its nuclear weapons programme, as a US intelligence report claimed last week, and believe the CIA has been hoodwinked by Teheran.

The timing of the CIA report has also provoked fury in the British Government, where officials believe it has undermined efforts to impose tough new sanctions on Iran and made an Israeli attack on its nuclear facilities more likely.

The security services in London want concrete evidence to allay concerns that the Islamic state has fed disinformation to the CIA.

The report used new evidence - including human sources, wireless intercepts and evidence from an Iranian defector - to conclude that Teheran suspended the bomb-making side of its nuclear programme in 2003. But British intelligence is concerned that US spy chiefs were so determined to avoid giving President Bush a reason to go to war - as their reports on Saddam Hussein’s weapons programmes did in Iraq - that they got it wrong this time.

A senior British official delivered a withering assessment of US intelligence-gathering abilities in the Middle East and revealed that British spies shared the concerns of Israeli defence chiefs that Iran was still pursuing nuclear weapons.

The source said British analysts believed that Iranian nuclear staff, knowing their phones were tapped, deliberately gave misinformation. “We are sceptical. We want to know what the basis of it is, where did it come from? Was it on the basis of the defector? Was it on the basis of the intercept material? They say things on the phone because they know we are up on the phones. They say black is white. They will say anything to throw us off.

”It’s not as if the American intelligence agencies are regarded as brilliant performers in that region. They got badly burned over Iraq.”