Tony Blair's official spin doctor Alastair Campbell has delivered a robust defence of his role amid claims he has abused his position, deliberately misled journalists and laid down the law to ministers.

Appearing before a powerful committee of MPs, he came under concerted attack from Tory members who demanded he released copies of the so-called "Campbell Tapes" of daily briefings to political journalists.

Mr Campbell denied ever describing Chancellor Gordon Brown as "psychologically flawed" or briefing against ministers including Frank Dobson and David Clark.

He said he knew he had been blamed for the attacks, but said he had no idea where they had come from.

"I have not briefed against any member of the cabinet. I happen to think you can put across the government's case in a coherent and coordinated way without briefing against anybody," he said.

The MPs particularly pressed him to hand over tapes covering a briefing Mr Campbell had given concerning a controversial telephone call earlier this year between the prime minister and Italian premier Romano Prodi.

Tapes row

One newspaper had suggested Mr Blair had attempted to intervene with his opposite number over a possible business deal by media tycoon Rupert Murdoch.

Mr Campbell dismissed the allegation, insisting he had never briefed one way or the other on the contents of the conversation, and said he would hunt for the tapes.

But, to the anger of the Tories, he signalled it was highly unlikely he would be able to provide them as they had probably been reused.

"You should not invest too much seriousness in them. They are not kept for posterity," he said.

He said he would consider whether written transcripts should be kept of all future briefings he gives to political journalists.

But he added it would have to be considered whether such a move was a good use of public money.

'Mildy obsessed'

Mr Campbell slapped aside claims he was more powerful than some cabinet ministers and, turning his fire on the Tory MPs, declared: "Your party is mildly obsessed about me and Peter Mandelson (minister without portfolio). My role is hugely overstated. I could not move policy even if I wanted to," he said.

He admitted he had written to social security ministers Harriet Harman and Frank Field warning them against leaks of government policy.

But he insisted he had been acting as the prime minister's official spokesman - not on his own behalf.

"In terms of anything I would say to a minister, it is not me that is speaking it is the spokesman of the prime minister."

The public administration committee is investigating the alleged politicisation of the civil service and the job of official spokesman, which was removed from the civil service by Mr Blair.

Mr Campbell's appearance had been anticipated for weeks by politicians and journalists who had been looking forward to a volatile clash.

David Ruffley led the assault

Tories David Ruffley and Richard Shepherd led the assault on the tapes - leading Mr Campbell to declare: "I can see 'the Campbell tapes' is going to be your headline."