'John bloody Birt', the secretive power at No 10

He's charged with laying out the Government's vision with his "blue-sky thinking" brief, but John Birt is rarely far from a storm.

He's charged with laying out the Government's vision with his "blue-sky thinking" brief, but John Birt is rarely far from a storm.

Unpopular during his time as BBC director general, he is said to be disliked by senior civil servants for his habit of declaring "Tony thinks..." in conversation.

Now John Prescott has launched an outspoken attack on "John bloody Birt" after The Independent revealed that he was drawing up secret plans within No 10 to expand nuclear power after the general election.

An exasperated Deputy Prime Minister was asked about Lord Birt as he toured an Edinburgh supermarket. Mr Prescott replied: "First of all, let's dismiss 'John bloody Birt'," he told the shopper.

"He might walk in and out of No 10, he might whisper in ears. There are thousands of advisers like that. He obviously thinks he is a bit more important. That is what advisers do ­ but they don't make decisions."

His comments reflected unease in government about the role of Tony Blair's unpaid strategy advisor, who has become one of the most secretive and enigmatic but potentially most powerful voices in Downing Street.

It was the second controversy to engulf the peer in a fortnight, after a wave of stories about his decision to divorce his wife and marry the former head of the National Probation Service.

Lord Birt, a friend of the Prime Minister for a decade, has been lobbying Mr Blair to become minister without portfolio after the general election, with a brief to drive through civil service and public sector reforms.

Such a move would be a hugely controversial promotion for the peer, who has been at the centre of a series of rows about his highly secret, and highly contentious policy advice.

The 60-year-old, who was given a life peerage by Mr Blair in 2000, was described by his successor Greg Dyke as "a man who worked upwards, someone who desperately wanted to be part of the power elite, part of the new establishment".

Critics say Lord Birt sits in on meetings between Mr Blair and cabinet ministers. He is known to work from offices in Downing Street ­ he was reported to have insisted on one ­ and the Cabinet Office. His office is reached by a spiral staircase, leading to rumours that he did not want to meet colleagues in the corridor.

The true nature of Lord Birt's work within Downing Street, and the importance or otherwise of his advice to Mr Blair, has remained one of the intriguing mysteries of New Labour.

John Birt was born in Liverpool in 1944. His father rose from a labourer to national sales director of the Firestone tyre and rubber company. He trained as an engineer, but rose through the broadcasting ranks, editing World in Action and producing Weekend World during the 1970s.

The quiet, Armani-wearing John Birt was one of the most controversial director generals the BBC has produced. The late playwright Dennis Potter famously described him as a "croak-voiced Dalek" in a phrase which was taken by many to sum up his love of management-speak.

He was criticised by stars and producers within the BBC for his reforms of the corporation. Since entering the House of Lords he has been linked with a string of controversial proposals, from diverting part of the BBC's licence fee to its commercial rivals, to abolishing the Cabinet Office, creating a new network of motorway toll roads and appointing the Prince of Wales as a "countryside tsar".

However, his work has been almost entirely secret, leading to no published reports. He shuns publicity.

Attempts by MPs and peers to obtain details of his reports, work programme or job have been thwarted by No 10, citing wide ranging exemptions of rules. Peers cannot question him in the House of Lords because he has no official ministerial job, and select committees cannot summon him because peers cannot be compelled to give evidence.

Norman Baker, Liberal Democrat environment spokesman, has hounded the government with questions about Lord Birt.

He said: "He has been producing blue skies thinking on a whole range of subjects which have never got anywhere. If Tony Blair wants someone to give him bad advice, that's up to him, but I want people to be accountable."