Simon Cowell is set to make this year's X-Factor Boot Camp the toughest ever.

The X-Factor boss is expected to shake up the show after being disappointed with last year's contestants, which he reportedly branded the "worst ever" in the show's history.

Hopefuls who have passed the recent audition stage of the show, will be expected to improve upon every part of their act, from styling to dancing and will work directly with producers to ensure they choose the right songs to suit their voices.

During last year's show, won by girl band Little Mix, Simon was reportedly worried that his reality show was becoming a flop.

According to The Sun newspaper, in one early morning phone call, he told the competing singers: "You all need to get your game up."

Simon, 52, also threatened to sack two judges from the panel - including head judge Gary Barlow.

This year there is thought to be extra pressure on The X-Factor, as ITV could axe the show in favour of a new prime time reality show to start next summer.

Speaking to the Daily Star, ITV boss Elaine Bedell said the network was "hungry for a big prime time event show."

Sources added the channel was willing to spend over £20m (€25m), but is struggling for ideas for a new format.

Elaine added: "We're not getting enough ideas put forward. The ideas need to have the production values of The X-Factor, Britain's Got Talent and I'm A Celebrity... and they need a major piece of talent."

Another senior source added: "X-Factor has had a brilliant run, but no show lasts forever.

"Over the past few years Simon Cowell has been the main source for many of our top hits but some feel that we've got too many eggs in one basket and we've become too reliant on one man."