Iain Duncan Smith has vowed to fight against any attempt to use the attacks in America as a means to give new powers to Brussels.

Speaking after a meeting with the 35 Tory MEPs at the European Parliament in Strasbourg, Duncan Smith said: "I will resist absolutely anything being pushed through on the back of the events of September 11."

Conservative sources have indicated to today's Telegraph that the new Tory leader is planning to withdraw his party's support for the new EU arrest warrant, considered to be a major step towards judicial union, which was approved by EU ministers in emergency meetings in the immediate aftermath of the attacks.