Speculation is mounting that Britain’s Got Talent. twosome Ant and Dec may leave ITV when their contract runs out at the end of next year.

The Sun reports that the pair – who also front a string of hits for the network including Saturday Night Takeaway and I’m A Celebrity…are upset by the way in which several of their shows were caught up in vote-rigging scandals.

And this week they also had to return their People’s Choice Award from the 2005 British Comedy Awards after it was revealed it was “fixed” by ITV bosses in order for them to win.

The prize should have gone to comedian Catherine Tate, but Ant and Dec ended up being given the prize because superstar Robbie Williams said he would only agree to attend the event if he could present an award to the pair.

They are said to be “appalled” by the revelations – and according to the paper, the network’s new boss Peter Fincham could have a tough job persuading them to stay with ITV.

“Ant and Dec have made it clear they’re highly upset,” a source told The Sun. “The gossip at ITV is that when their contract runs out they may not stay exclusive with ITV.”

“They are not really BBC people,” the source added, “but they have their own production company, Gallowgate, and could very easily make shows for every broadcaster and channel.

It would be a blow for ITV if they didn’t manage to keep them exclusive. Along with Simon Cowell they are their heavy hitters.”