The X Factor is once again surrounded by controversy after the usual semi-final public vote was scrapped, allowing the judges to pick this year’s finalists.

Shortly after the judges’ vote, which saw Cher Lloyd advance to the final and Mary Byrne leave the competition, angry viewers blasted the ITV1 switchboard with complaints and took to websites in their thousands claiming the show was ‘more corrupt than Fifa’.

For the first time in the show’s history, X Factor bosses introduced a sing-off in the semi-finals – giving the judges a chance to save an act rather than leaving the decision up to the voting public.

The move even came after host Dermot O’Leary told viewers on Saturday night’s episode: “Your votes and your votes alone can get your favourite act safely through to the final.”

None of the viewers were told there had been a change in the format of the semis and that a sing-off had been introduced, but according to ITV sources, the decision to change the format was ‘made weeks ago’.

A spokewoman said: “As the show evolves there are always changes to the format”.

Fans of the show were also left reeling today after Simon Cowell revealed that he had arranged a duet between Cheryl Cole and Cher on the finalist’s debut album.

He confirmed live on the show that the pair would sing together and Cher’s £2million record deal will make her the big winner of the series, whether she wins or not.

Mary’s departure leaves Cher, Matt Cardle, One Direction and Rebecca Ferguson to battle it out for the winners title in next week’s X Factor 2010 final.