Jules O'Dwyer may have won the 2015 series of Britain's Got Talent, but it was her Border Collie Matisse that was the real star, especially after he went walkies on a tightrope in the grand final.

Now it has emerged that trick, which featured O'Dwyer as a policewoman pursuing the sausage thief Matisse, was actually performed by a second hound, a nippy stunt dog named Chase.

2015 Britain's Got Talent winner Julie O'Dwyer and the stunt dog that performed her winning trick, Chase. Credit:Youtube

Britain's communications regulator, Ofcom, has found the series broadcaster ITV breached the Ofcom code after 1175 viewers complained. Perhaps they noticed the pooch that buried runner-up, magician Raven, had a darker coat and different head markings from Matisse.

"Broadcasters inviting viewers to vote using premium rate numbers have a particular responsibility to ensure the audience is clear about what they are voting for," Ofcom said in a statement.