Britain's Got Talent 2015, dog double: Simon Cowell 'feels like an idiot' after Jules and Matisse scandal

Cowell 'raised his voice' at producers after hundreds of viewers complained

Chase walks the tightrope instead of Matisse in the Britain's Got Talent 2015 final (Dymond/Syco/Thames/Corbis)

Simon Cowell was left "feeling like an idiot with his head in his hands" after finding out that Britain's Got Talent winner Jules O'Dwyer had used a doggy-double for that memorable tightrope stunt.

The trainer triumphed over magician Jamie Raven on Sunday night after wowing viewers with her clever dog Matisse. But it was later revealed that another collie, Chase, had performed the most heart-stopping part of her routine and then been hidden.

TV watchdog Ofcom received 507 complaints from voters believing they were "tricked", while ITV reported another 130.

ITV boss Peter Fincham claimed the decision not to come clean about the use of Chase was a "judgement call" but should have been made clearer, but lead judge Cowell was angrier about the "c**k up" and producers felt his wrath.

"The moment I found out I literally put my head in my hands. I spoke to a lot of people after and I did raise my voice," he told the Daily Mirror. "But it was mainly people owning up to it. They felt embarrassed, they felt frustrated, they felt stupid but you've got to man up to this stuff.

"The producers are absolutely gutted. I was so depressed for the show, for Jules and for the producers themselves because they are not horrible people. They didn't think how it would appear.

"I was frustrated because I didn't really know what I was judging until afterwards so I felt like a bit of an idiot."

Cowell added that no-one had intended to conceal Chase's involvement but regretted the "cloud" that now hangs over O'Dwyer.

"I want people to feel proud of her and that she did well and she should be happy," he said, after the 48-year-old won the £250,000 cash prize and a spot on the Royal Variety Performance line-up.

O'Dwyer has explained that she used Chase for the tightrope stunt because Matisse is scared of heights.

"I was disappointed when people said I allegedly hid Chase and I was trying to make it like Chase was Matisse," she said. "That's not so. I introduced Chase in the semi-final and I said Chase is Matisse's best mate. Why put the pressure on the dog when I already have another dog who can perform it on television?"

However, Chase was not brought out when O'Dwyer and Matisse faced the judges, something Cowell admits "should have happened".

Ofcom is assessing complaints before deciding whether or not to investigate.