Simon Cowell and Pete Waterman are two of the show's judges

His odds have been cut with bookmaker Ladbrokes from 4/6 to 1/2 after he was backed with a "sustained" string of betting during the past 48 hours.

Sam, 17, is in the final four of the ITV1 show alongside Michelle McManus, who is 4/1, Chris Hide (9/2) and Mark Rhodes, rank outsider at 10/1.

The Pop Idol 12 are also favourites for the Christmas number one single.

Susanne Manning became the latest contestant to be voted off the show at the weekend after her performance of Cry Me A River was deemed to be the poorest.

Susanne said she thought she had been removed because of newspaper reports that she had made disparaging comments about rival contestant Michelle's weight.

After the show, she told BBC Radio 1 she was "shocked and upset" about being accused of picking on Michelle because she herself weighed 14 stone when she was 14 years old.