Torin Douglas reports: "He stunned the BBC by saying he was leaving"

Mr Lynam was due to present BBC One's flagship football show Match of the Day, which begins a new series this Saturday.

He has instead signed a four-year deal with the corporation's commercial rival. He described the move as a "challenge".

He said: "Leaving the BBC after 30 years was not an easy decision to make, but it was time for a new challenge - and it's no secret that live football is what I love best.

"This sort of opportunity does not come along every day and the chance to anchor ITV's extensive peak-time Champions League coverage, as well as the FA Cup and other major football, was just too tempting to turn down."

Mr Lynam said he had received offers from ITV in the past, but this one had come at the right time for him personally.

He added that he had taken advice and believed he was not in breach of his BBC contract as a result of deciding to leave.

After three decades at the BBC, he said he had become "a little stale", but he insisted this was not an attack on the corporation's sports arm.

"In no way am I going to be here today to knock BBC Sport. They've done a marvellous job for me and I hope I've done the same for them. I'm very sad in many, many ways to be leaving."

Another loss for BBC sport

His departure will be seen as another loss for the BBC, which has seen its sports coverage dwindle in recent years as commercial station put forward ever higher bids for key events.

Just a month ago, the BBC's controller of television sport, Mike Miller, said: "The BBC has more to offer sport than money: its audiences, its production values, its long-term loyalty and people like Des Lynam, Steve Ryder and Sue Barker nobody else has."

ITV is welcoming "Britain's pre-eminent football presenter"

Mr Lynam had been with the corporation for 30 years and was regarded as one of its star performers.

He began his BBC career as a boxing commentator and went on to anchor Sports Report on Radio 2, before switching to TV and becoming presenter of Grandstand.

He fronted the Wimbledon, Olympic Games and World Cup coverage and branched out into non-sports programming.

'Special style of presentation'

Bob Shennan, Head of BBC Sport: "Des leaving is a big disappointment, but no presenter is bigger than BBC Sport"

He has long been regarded as one of the BBC's prime assets, making his name through his unflappable demeanour and relaxed charm.

ITV controller Brian Barwick said the presenter would provide the "perfect match" for increased football coverage on the channel.

He said: "Desmond is a unique talent in British television - a much-loved and much respected figure.

"We are looking forward to him bringing his special style of presentation to ITV.

"We have an immensely strong portfolio of live football, and with Des we now have the perfect match."

ITV's director of programmes, David Liddiment, said: "ITV started to invest heavily in football in the early '90s as the country's favourite game started its renaissance.

"We've built upon this investment with our new four-year Champions' League contract.