Islamic extremists: David Cameron's foot-shooting habit

This is the second time that David Cameron has shot himself in the foot when calling for Islamic extremists to be banned or expelled:

David Cameron was under fire yesterday after it emerged that the radical Muslim scholar Yusuf al-Qaradawi had been admitted into the UK when the Tory leader was working in the Home Office.
Cameron, at prime minister's question time on Wednesday, demanded that Gordon Brown ban al-Qaradawi: "He was banned by a former Conservative home secretary, so why will the government not ban him?"
But al-Qaradawi was allowed into the country five times by a Conservative home secretary, Michael Howard. On at least one of those occasions, in August 1993, Cameron was a special adviser to Howard.

The last embarrassment for Cameron, in a similar vein, is related here. In July 2007 he asked for an Islamic group to be banned and then it was revealed that he had thanked the same group, in writing, just a few months before.