Leon Jackson won The X Factor ‘fair and square’, ITV has said as the number of complaints about his shock victory shot up to more than 1,500.

Fans of runner-up Rhydian Roberts have accused TV bosses of fixing the result after finding phone lines jammed during Saturday night’s show.

The Welsh singer had been the hot favourite throughout the series – but lost out in the final after a last-gasp surge of votes for Leon.

As the number of complaints to Ofcom rocketed, ITV stepped into the row to reassure viewers and deny a fix.

The broadcaster said in a statement: “We know there are many Rhydian fans who are disappointed that he did not win, but the simple fact is that Leon won the X Factor fair and square.

“Rhydian and Leon were both very strong finalists, so it is not surprising that they both had avid fan bases and that people voted in their millions.

“However, Leon performed strongly across the series and was the outright winner on the night by a full 10 per cent of the vote.

“We never reveal results of the show to the viewers, judges or the production team throughout the series to ensure that voting patterns are not influenced by that information.”

There was just one per cent between Leon and Rhydian before they sang their respective versions of new single When You Believe.

But after they had performed, there was a surge in support for the 18-year-old Scot.