Simon Cowell has been blasted by his arch rival Simon Fuller, who dismissed the X Factor as the TV equivalent of wrestling. Bitter Fuller, 49, is furious that Cowell is quitting American Idol after sealing a £100million deal to take the show to the US.

But he insisted that Idol will survive the TV star’s exit because the show has a “boxing-type” purity and is only about talented singers. “I want Idol to be purely about talent,” stormed  Fuller. “We’re not going to be led into the mud, we’re going to stay on our hill.”And backing critics who have attacked X Factor for being a freak show, Fuller added: “The Susan Boyle phenomenon is not based on anything but the bizarre.”

And in another bitchy aside he declared: “I have integrity about music and believe talent that comes out of Idol is legitimate.”The extraordinary attack could spark another war between the two Simons, although Fuller insisted their rivalry was “grossly exaggerated”. They have fought and then kissed and made up on countless occasions.

But Fuller is known to resent Cowell’s success – and his livewire personality. “Fuller has got brains and instinct but has the personality of a wet weekend in Hastings,” said an insider, adding: “Cowell has the lot.”

Cowell has been nothing but complimentary of everyone still connected with American Idol. He released a statement saying how much he enjoyed his time on the show and wished them every success. The source added: “This could get very messy.” Team Cowell last night refused to comment. A US telly source added: “It seems Mr Fuller has a lot of issues which he needs to work through.”  US X Factor debuts in 2011 with Cowell as a judge and Cheryl Cole his probable sidekick.