Alastair Campbell spent Saturday afternoon watching Burnley play

The prime minister's "spin doctor" announced his resignation on Friday, saying he would leave within the next four to five weeks.

At the same time Downing Street said it would be shaking up its media operations, with a "new communications structure" to be announced next week.

Mr Campbell's departure was greeted with a mixture of regret and delight from fellow political figures.

Liberal Democrat chairman Mark Oaten described the announcement as one last piece of spin, designed to deflect attention from other issues facing the government.

"When we should be talking about what is happening in Iraq where our soldiers are being killed and peace is a long way off, he has taken those headlines away and made himself again the major news story.

He wanted to go with his reputation intact and when it would do no damage to his boss The BBC's Nick Assinder Burnley win to cheer Campbell Blair loses his 'king of spin'

"It is a masterstroke," he told BBC Radio 4's Today programme.

And Tory deputy leader Michael Ancram said Mr Campbell's absence would not change underlying problems with the government.

"He leaves behind Tony Blair who is now so imbued with the same culture of spin and deceit that [it] won't change things," he told Today.

'Time to go'

Environment Secretary Margaret Beckett, who strongly defended Mr Campbell's record, acknowledged his successor would need to adopt a lower profile.

"One of the most important things is the way that Alastair Campbell's image has been used and abused against the government," she said.

It is time to move on and do other things, and let others support the prime minister in the next phase of the government's programme of change Alastair Campbell Alastair Campbell: Why I'm going Campbell's career in his own words

"I am sure that David Hill will be trying to find ways to avoid that, but whether he will succeed remains to be seen."

Mr Campbell told the BBC his reasons for leaving were simply to quit such a high-pressure role and "to get a life back for me and my family".

The father of three, and partner of Cherie Blair's adviser Fiona Millar, who is also quitting, said: "I just felt this was the right time to go... about the right time to go and let someone else come in and do the job."

His resignation was not related to the ongoing Hutton inquiry into the death of government weapons expert Dr David Kelly, he said.

"I agreed with the prime minister last April that I would definitely go in the summer and I don't want to say anything about the Hutton Inquiry at all."

Mr Blair said he was sad to see his top aide go, describing him as "an immensely able, fearless, loyal servant of the cause he believes in, who was dedicated not only to that cause but to his country."

And John Prescott said Mr Campbell, whom he had known for 20 years, would be "very much missed".

'Live issue'

But others questioned Mr Campbell's role in the Iraq dossier and subsequent row with the BBC which led to Dr Kelly's death, still under investigation at the Hutton Inquiry.

An outstanding example of how a political party has to defend itself against biased and offensive media attention Alex, UK Your views on Campbell Praise and criticism for Campbell

Liberal Democrat deputy leader Menzies Campbell said the inquiry still had "a long way to go and Alastair Campbell's role, as a matter under investigation, is still a live issue".

And Conservative MP and member of the foreign affairs committee Richard Ottaway said Mr Campbell was "quite clearly going to take the full blame to protect the prime minister".

Mr Campbell's successor David Hill was Labour's communications chief in the 1997 general election and former press aide to ex-deputy leader Roy Hattersley.

He has been described as equally tough and combative as Mr Campbell, but also someone who could mend the strained relationship between the media and Downing Street.

"Hill finds it almost pathologically impossible to deceive or dissemble," says his former boss Mr Hattersley, writing in the Guardian.