The departure of the Downing Street communications chief, Mr Alastair Campbell (46), is to be followed by a reorganisation of the media and public relations operation in the British Prime Minister's office.
Mr Campbell will be succeeded by Mr David Hill (55), a former director of communications for the Labour Party, who is expected to play a somewhat different and less high-profile role than his predecessor.
The British government, and Mr Tony Blair in particular, have come in for strong and sustained criticism, especially in the recent past, for an alleged over-emphasis on presentation and "spin" at the expense of substance in politics.
This came to a head during the Kelly affair with critics of the government alleging that an obsession with media coverage and presentation added to the pressure on Dr David Kelly, who apparently committed suicide after he came under sustained media and parliamentary scrutiny.
Mr Campbell gave evidence last week to the Hutton Inquiry, set up to examine the circumstances leading to Dr Kelly's death. He was generally expected to leave his job later in the year, after the inquiry had concluded, and his sudden announcement yesterday came as a surprise in media and political circles.
The Kelly affair began when BBC journalist Andrew Gilligan reported a claim, allegedly made by Dr Kelly, that the government falsified a dossier on Iraqi weapons of mass destruction to enhance the case for going to war.
Mr Gilligan subsequently named Mr Campbell as having allegedly inserted a statement in the dossier that Iraq could activate its weapons within 45 minutes. Mr Campbell vehemently denied the claim.
As one of Mr Blair's most senior aides, Mr Campbell played a very active role behind the scenes in the Northern Ireland peace process. He is expected to return to his former profession as a journalist, writing mainly about politics and sport.