This is taken from BBC News Online:

Thursday, 15 December 2005, 16:36 GMT
Lord Birt quits as Blair adviser

Lord Birt Former BBC director general Lord Birt has quit as strategy adviser to Tony Blair, Downing Street has announced.

Lord Birt, a "blue-skies thinker" in Mr Blair's strategy unit since 1999, will take up a position with Terra Firma, a private equity investment company.

Mr Blair said his "hardheaded analysis" had been "invaluable over a whole range of issues".

"I am very grateful to him for all he has done during his time at Downing Street," the prime minister added.

Lord Birt had advised on issues ranging from the future of transport to the UK's long term energy supplies.

Terra Firma, founded by Guy Hands, owns a number of companies, including Odeon and UCI Cinemas and the German motorway service operator Autobahn Tank & Rast.

Under the terms of the departure deal, Lord Birt will be forbidden from personally lobbying UK ministers or officials on their behalf, for a year after leaving Downing Street.

In a statement, Lord Birt, 61, said: "I told the prime minister at the time of the election that, for personal reasons, and with regret, I would need to leave No 10 by the end of the year.

"It has been a privilege to advise Tony Blair over the past six years.

"I leave with an abiding sense of a radical, energetic and reforming prime minister, crystal clear about his goals, and of a government and civil service ever more capable of achieving them."

Lord Birt has recently been the focus of controversy over his refusal to appear before committees of MPs who wanted to question him about his role in Downing Street.

Liberal Democrat MP Norman Baker said: "This is the best bit of news this week. The sun has certainly come out as the blue skies thinker disappears."

Lord Birt, born in Liverpool and educated at Oxford University, was director general of the BBC from 1992 to 1999.

He also worked at Granada TV and London Weekend Television.