The Business Secretary has spoken frankly about his rows with the Prime Minister, saying the rift between them has been healed.

Speaking on the BBC yesterday, Lord Mandelson also dismissed stories about his relationships with rich businessmen while in his former role as the EU Commissioner for Trade.

The emnity between Gordon Brown and his new Cabinet minister goes back to 1994 when he chose to back Tony Blair over Mr Brown for leader of the Labour party in 1994.

“I think both of us looking back would say we wasted a lot of the energy and time that we could otherwise have devoted to the success of the government by not repairing our relationship sooner,” Lord Mandelson said yesterday.

He also defended Mr Brown, who was a close friend before their falling out, comparing him favourably with the Tory leader.

“He’s not a showy person, he’s not an attention-seeking person, he’s not swinging around like a pendulum in the way that David Cameron is,” he said.

Less than a year after his appointment as Secretary of State for Trade and Industry in 1998 Peter 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.

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.

The former Cabinet minister resigned but was later cleared of any wrongdoing. He has been the UK’s appointee to the European Commission since November 2004.

Since he returned to frontline British politics earlier this month, Lord Mandelson, the first gay person to sit in the Cabinet since 2001, has faced questions about his decision to accept hospitality from a Russian aluminium magnate.

“I have a very clear view of my public role and the responsibilities I have in that public role and how I spend my private time,” Lord Mandelson told the BBC.

“There has been innuendo in the newspapers that I gave favours or I gave benefits as trade commissioner to certain individuals because of my personal friendship with them.

“The entirety of the European Commission, the director general for trade himself, has made clear there is not one jot of truth in that, that it is 100% false.

“You cannot do business as a European trade commissioner in Russia, India, China, South Africa, Brazil, all the big emerging economies of the world, without having contact with the big business and economic figures in those countries as well as the political figures.”