THE journalist at the heart of the Hutton Inquiry resigned from the BBC last night but insisted the corporation had been the victim of a "grave injustice".

Andrew Gilligan was the third person to quit the corporation over the affair, following the departures of director general Greg Dyke and chairman Gavyn Davies.

Mr Gilligan admitted he had made mistakes, but insisted most of his story was right and the Government had "sexed up" its dossier on Iraq's weapons of mass destruction - a charge which the Government was cleared of by Lord Hutton.

Mr Gilligan said: "I love the BBC and I am resigning because I want to protect it.

"I accept my part in the crisis which has befallen the organisation.

"But a greater part has been played by the unbalanced judgements of Lord Hutton."

Mr Gilligan's resignation came as Alastair Campbell gave his first public talk, to a capacity audience of 400 in the North-East last night.

At the Customs House in South Shields, Tyneside, the former Downing Street spin doctor talked about his life, from a student busking in Nice to his time as one of the Prime Minister's key aides.

He declined to comment about Mr Gilligan's resignation. But he said he wanted to put behind him the row between the Government and the BBC and said he had always supported the independence of the corporation.

He also made a robust defence of Tony Blair, saying he was a "decent guy doing a decent job", and poured scorn on some sections of the media - particularly the Daily Mail, which repeatedly said that Mr Blair was not to be believed.

Mr Campbell said: "It is trying to break the link of trust between those we have elected from doing the job they were elected to do."

His talk came after a disagreement with the BBC's Look North programme yesterday. Look North issued a clarification after presenter Colin Briggs said in his lunchtime bulletin that the Customs House audience would be "full of journalists".

Following an approach on behalf of Mr Campbell, the programme told viewers in its 3.25pm bulletin: "On our lunchtime Look North we implied that the majority of the audience would be journalists. In fact, there are 25 known journalists in an audience of 400 and we are happy to make that clear."

Last night, a BBC spokesman confirmed an approach had been made on behalf of Mr Campbell, but said they had looked at the report and decided they would make a clarification.

"We haven't made any apology," he said. "We looked at the report that went out at lunchtime and decided that we needed to make some kind of clarification, and that's what we did in our mid-afternoon bulletin.

"As far as we are concerned, there's no problem between us and Alastair Campbell. We are just covering a story with a man who's in the news at the moment like everyone else is."

Meanwhile, Mr Dyke said he did not accept all the conclusions reached by Lord Hutton and said he was preparing a detailed response to the former law lord's report.

He said: "I will at some stage either write or broadcast a considered opinion on Hutton. It might take me a few days. It might take me two weeks."

And he attacked the response to the Hutton Report by Mr Campbell.

"I think he has been remarkably ungracious," said Mr Dyke.

The BBC announced yesterday it would be launching an internal investigation into its failings over the affair. Acting director general Mark Byford will head the probe in a bid to ensure there is no repeat of the mistakes which led to Lord Hutton's criticisms of the BBC.