In an article for the Sun - headlined Reports of the BBC's death have been grossly exaggerated - Sir John argues that the licence fee "remains remarkable value for money".

"I know it is fun to knock the BBC. Sometimes we deserve it," he says.

"But in the last few years we have made tremendous improvements. Not just in the quality of our programmes.

Sir John: Commitment to quality

"We have sorted out our finances and become far more efficient. And we do more for schools than any other broadcaster."

Sir John adds that he is clear about the corporation's role

"No cutting corners on quality. Audiences before advertisers. Something before everyone. An unswerving commitment to the truth.

"The future looks promising."

Auntie under pressure

The BBC has come under fire on several fronts in recent weeks.

MPs criticised it for being out-bid by Channel 4 in the battle for the TV rights to Test match cricket.

Then a House of Commons committee branded the corporation's management as "lazy and arrogant".

The level of investment in new technology has also been attacked as has the BBC's ban on the broadcast of details of the private life of the Trade Secretary, Peter Mandelson.

'Tide is against us'

Sir John says he regrets the loss of Test cricket, but sees it as almost inevitable.

Channel 4: Digital competitor

"A tide of money is now flowing against us and there is a limit to what the BBC can spend in sport without damaging other services," he says.

He also rejects the arguments of critics who say the BBC is going into digital technology before many people have the necessary equipment to receive the enhanced broadcasts.

The BBC will be left behind, he believes, if it does not compete with the services being offered by rival such as Sky and Channel 4.

"Fifty years ago we used to broadcast TV programmes to only a handful of homes. We didn't wait for sets then. We can't wait now," he said.

Sun calls for change

However, the Sun - which like Sky TV is owned by Rupert Murdoch's News Corporation - remains unimpressed.

In an editorial running alongside Sir John's comments, the Sun says a new face is needed to modernise the BBC and nominates Channel 4 Chief Executive Michael Jackson.