A senior al-Qaida operative deliberately planted information to encourage the US to invade Iraq, a double agent who infiltrated the network and spied for western intelligence agencies claimed last night.

The claim was made by Omar Nasiri, a pseudonym for a Moroccan who says he spent seven years working for European security and intelligence agencies, including MI5. He said Ibn Sheikh al-Libi, who ran training camps in Afghanistan, told his US interrogators that al-Qaida had been training Iraqis.