David Cameron (left) appeared on Jonathan Ross's show on Friday

Ross asked Mr Cameron if he had had schoolboy sexual fantasies about former Prime Minister Margaret Thatcher.

"I stand by it. It was a perfectly valid question," Ross told BBC Radio Five Live.

Former Tory minister Lord Tebbit called the interview "obscene" and criticised Mr Cameron for appearing on the show.

Initially, the BBC received 11 complaints after the show was broadcast, but following media reports about interview the figure rose to 360.

Ross said his show did not set out to upset people.

"I wouldn't want to do that, even though upsetting Norman Tebbit has given me some small sense of satisfaction because he's spent 12 years upsetting me," he joked.

Side-stepped

"If Mr Cameron had felt awkward about that question and answer sequence we would have removed it, but none of his people thought it was a problem and neither did the people I work with, so that's why we didn't," he added.

Mr Cameron changed the subject when asked if he had fantasies about Lady Thatcher "in stockings", and later laughed off another suggestive question.

The exchange took place during last week's BBC One show, Friday Night With Jonathan Ross.

Lord Tebbit said on the BBC's Sunday AM that Mr Cameron had made an "awful mistake" by appearing on the Ross show.

He said Mr Cameron had been "thoroughly embarrassed by Ross using the occasion for making an obscene attack on - and I use the word literally, obscene - on Margaret Thatcher".

"He should never have been there," he said.

The BBC said it stood by the interview, screened after the 9pm watershed.