Catherine Tate was robbed of a prize at the 2005 British Comedy Awards, ITV has admitted.

The broadcaster says the People’s Choice Award was given to Ant and Dec instead – to ensure that Robbie Williams came to the ceremony.

Independent law firm Olswang has issued its report into the scandal, which said: ‘Robbie Williams was invited to present an award. It was understood that he would be happy [to do so] if the recipients were Anthony McPartlin and Declan Donnelly. In order to ensure his attendance, this assurance was given.’

The company was called in by ITV to investigate irregularities in the phone vote. They discovered that Tate's show was the rightful winner, and there was ‘insufficient evidence’ to explain why Ant and Dec's Saturday Night Takeaway had been given the prize.

Investigators also found that, as previously reported, the final section of the ceremony was broadcast with a half-hour delay, as ITV1 aired the 10.30pm news while the ceremony continued in the studio.

After the show returned to air, viewers were still asked to vote for the People's Choice Award, despite the fact that the trophy had already handed out.

The deception emerged as ITV was fined £5.68m over its use of premium rate phone lines by media regulator Ofcom, many involving competitions on Ant and Dec's Saturday Night Takeaway.

The pair were said to be ‘absolutely appalled’ by the error, and their spokesman said that they would be returning the award.

Oslwang’s report said: ‘There is no suggestion that Robbie Williams, Anthony McPartlin or Declan Donnelly were aware of any of these issues.’

The scandal surrounding the phone-in meant that ITV refused to air last year’s awards, even though they went ahead as usual in London.

Production company Michael Hurll Television said it was ‘embarrassed and deeply apologetic’ by the voting irregularities.