Business Secretary Peter Mandelson called the Prime Minister’s office to seek help after he fell ill on Sunday night, it has emerged.

The former EU Commissioner, who returned to the government on Friday after more than seven years away from frontline British politics, underwent surgery yesterday to remove a kidney stone.

He is the first gay man to sit in the Cabinet since 2001.

The Mirror reports that Mr Mandelson called Downing St at 3am on Monday morning reporting he was very unwell.

The Prime Minister’s aides then contacted Lord Darzi, a leading surgeon and minister of health, who went to the home of the Business Secretary.

A source told the paper: “Lord Darzi drove him in his own car to St Mary’s Paddington.”

Kidney stones were diagnosed but Mr Mandelson left hospital later that morning to attend the first meeting of the new ‘economic war cabinet,” the National Economic Council.

He underwent surgery yesterday.

Mr Mandelson, 54, has not been out of the headlines since his shock return to the Cabinet last week.

Over the weekend he let it be known he phoned Tony Blair for advice after he was offered his third job in the Cabinet, while he denied that at he had rubbished the Prime Minister just a few weeks ago at a dinner with the Shadow Chancellor George Osborne.

Mr Mandelson’s return to frontline British politics after more than seven years was the most eye-catching appointment in Gordon Brown’s reshuffle.

They were regarded as sworn enemies since Mr Mandelson chose to back Tony Blair over Mr Brown for leader of the Labour party in 1994.

Less than a year after his appointment as Secretary of State for Trade and Industry in 1998 Mr Mandelson was forced to resign after it emerged he purchased his west London home with an interest-free loan from a fellow Labour MP whose business dealings were under investigation by the department.

Many thought his career was over but just ten months later Tony Blair made him Secretary of State for Northern Ireland.

Mr Mandelson was an effective negotiator and his efforts to bring peace to the province were praised on both sides of the political divide.

However, in January 2001 he was implicated in another scandal after it was alleged he intervened to try and get British citizenship for an Indian businessman who was being investigated for corruption.

Mr Mandelson resigned again. He has been the UK’s appointee to the European Commission since November 2004.

The Prime Minister has defended his decision to appoint Mr Mandelson.

At a press conference on Friday Mr Brown said their relationship was “very good.”