Former cabinet minister Peter Mandelson helped devise Downing Street's strategy for dealing with Alastair Campbell's resignation, according to press reports.
Mandelson reportedly paved the way for media changes
The reported involvement of the former Labour communications director in the talks has drawn fire from both Conservatives and a leading trade unionist.
Mr Campbell announced his much-predicted departure as Number 10 media chief on Friday.
Downing Street's media operations are to be revamped in the wake of his resignation, with Mr Mandelson reportedly part of drawing up the changes.
Whatever his role, the main blueprint for the new press operation is likely to be based on a government sponsored review of the work of political advisers at Number 10.
Chain of command
Bob Phillis, head of the Guardian Media Group, is believed to have recommended that special advisers in the Downing Street press operation should not be able to give orders to civil servants.
Mr Campbell and Number 10 chief of staff Jonathan Powell in 1997 became the first political appointees to be able to issue commands to civil servants.
Mr Phillis' report is also said to recommend that Mr Campbell's successor, David Hill, should also have to answer to a senior civil servant.
The Daily Telegraph and the Daily Mirror newspapers suggest Mr Mandelson had a key role in talks over the revamp.
The Telegraph also says former BBC director-general Lord Birt and Matthew Taylor, head of the Institute of Public Policy Research think tank, gave their advice.
Mr Mandelson told the newspaper he had always advised Mr Blair - something he and now Mr Campbell would continue to do.
"I have always been there - I have always done it," Mr Mandelson was quoted as saying. "We believe in him (Tony Blair)."
Asked about Mr Mandelson's role, the prime minister's official spokesman on Monday said: "Mr Mandelson is not a member of the independent Phillis review group and I think that's what's significant."
The spokesman said the timing of the announcement of the changes would depend on the Hutton inquiry.
"We're anxious not to get in the way... we have to be slightly sensitive to that," he added.
Back seat drivers?
The involvement of one of the architects of new Labour, who has twice resigned from the cabinet, has drawn criticism as the debate over government "spin" continues.
Sir Bill Morris, outgoing general secretary of the Transport and General Workers' Union, warned of the dangers of using unofficial advisers.
He told BBC Radio 4's Today programme: "There are a lot of talents in
the Labour Party. Peter Mandelson has got a tremendous amount of talent, so has
"But I hope the prime minister doesn't bring back the back seat drivers. We
have got a new director of communications who will take office shortly.
"He must not be undermined. The prime minister must have one source in terms
of the direction of communicating the government's policy.
"We don't want the
back seat drivers - that's a recipe for chaos.
"We have to judge the prime minister and the government on its record. It has
delivered the best economic programme of any government since 1945. We have some
issues to address, and these are the social issues."
A spokesman for Conservative leader Iain Duncan Smith told the Telegraph: "No sooner does one spin doctor leave than he is invited back through the revolving door."