His position became untenable after speculation he was the source of leaks that gave the media the scalps of Peter Mandelson and Geoffrey Robinson before Christmas following the disclosure of a secret loan.

Now the Treasury press secretary is the latest victim of the scandal which rocked the Labour government.

Gordon Brown is a close friend

Mr Whelan made his name for his off-the-record calls to journalists on his mobile phone from a Whitehall pub.

He was Chancellor Gordon Brown's press spokesman as Alastair Campbell is prime minister Tony Blair's "official spokesman".

Like Mr Campbell, a former political editor on a tabloid newspaper, both are from the old school of press relations.

Although he is known for his boisterous cockney expletives, Mr Whelan, who is 44, is not particularly working class.

From city dealer to communist

He is the son of a civil servant who went to a minor public school in Surrey.

He took a degree in politics at the City of London Polytechnic before becoming a foreign exchange dealer in the City.

But his left-wing sympathies led him to join the Amalgamated Union of Engineering Workers, working for trade unionist Jimmy Airlie.

At the same time, Mr Whelan joined the Communists - and remained until 1990.

After Labour's 1992 general election, Mr Whelan was recruited to the party by Peter Mandelson. Mr Whelan said he would only work for Mr Blair or Mr Brown.

Later, one of Mr Whelan's favourite lines would become: "Peter Mandelson may have told you that, but it's not true."

The first row with Mr Mandelson came after the famous Granita dinner, where Mr Brown stood aside in the race to lead the party after John Smith's death.

Mr Mandelson informed the media of the development without consulting Mr Whelan.

The loss of Mr Whelan, less than a month after the resignation of Geoffrey Robinson as paymaster general, will come as a bitter blow to Mr Brown.

Mr Whelan was not merely an aide to the chancellor, he is also a close friend.

'Out of control'

He may be boastful and occasionally foolish, but he is described as loyal and often shrewd.

His robust manner complements the chancellor's shy, controlled demeanour.

However, his opponents have described the former spin doctor as "a killing machine", "out of control" and a "serial killer".

After Labour's election victory in 1997, Tony Blair is alleged to have ordered Mr Whelan be sacked or brought within the control of Number 10 but the chancellor refused.

Gordon Brown and girlfriend Sarah Macaulay: Whelan tipped-off the media

Although a successful spin doctor, Mr Whelan has made many enemies over the years through his bruising technique.

Robin Cook is believed to have suffered at Mr Whelan's hands. In the run-up to last summer's Comprehensive Spending Review, it "emerged" before any formal announcement the Foreign Office budget was a target for cuts.

Cynics also suggest Mr Whelan was not a million miles away from some stories that appeared about Mr Cook and his extra- marital affair with Gaynor Regan, who is now his wife.

As well as spinning on Treasury policy, Mr Whelan has also been instrumental in promoting Mr Brown's personal life.

One of his most successful "leaks" was the news Mr Brown was romancing public relations consultant Sarah Macaulay.

However, Mr Whelan's demise comes for something he has adamantly denied leaking - that Mr Mandelson borrowed £373,000 from Mr Robinson to buy a Notting Hill mansion.