Iain Duncan Smith's supporters have denied accusations that he performed a double u-turn on Section 28.

The shadow defence secretary's spokesman said: "Section 28 stays in place because it protects the vulnerable and will stay there until someone comes up with something that is as good if not better."

The Clarke camp said Duncan Smith was backing down after suggesting at the weekend he would reconsider the legislation. "He has snapped under the weight of his own supporters with a policy that wouldn't even hold for 24 hours," said Clarke's spokesman.

Clarke also said polls showing him trailing his rival were inaccurate as "no one had the first idea" who would win the leadership contest.