Lord Mandelson, the former business secretary, has said he is proud to have blazed a trail for gay politicians.

In an interview to promote his memoirs, he was quizzed by the Times about his position as the “the most powerful gay man in the country” when he was seen as the de facto deputy prime minister in Gordon Brown’s Labour administration.

He has never attended any Pride events or Downing Street gay receptions in his role as a politician and has never talked openly about his sexual orientation, instead choosing to guard his privacy.

However, Lord Mandelson said he was “rather proud” of having demonstrated that people can reach the top regardless of whether they are gay or straight.

He said: “I would hate to think that I take a stand because I have one sexuality, or one sexual orientation.

“I think it’s important that people should be able to get to the top of politics – or whatever profession they aspire to travel to the top of – irrespective of what they are.

“I think I’m actually quite a good role model for people who, without any fuss or bother, without any self-consciousness or inverse or other discrimination, (are) able to make it in politics, to make it in public life, to make it to the top places in government of our country.

“That shows a lot of people that you don’t have to be worried or ashamed or self-conscious. It’s your ability that counts. You can be who you are, what you are and still get to the top in Britain.

“I’m rather proud of that. If I’ve demonstrated that, and provided a role model for that, then I think I’ve done a service.”

Lord Mandelson’s memoirs, The Third Man, are being serialised in the Times this week.

He has reportedly infuriated former prime minister Tory Blair, who he was a close ally of, by the portrayal of his leadership.

Lord Mandelson claimed Mr Blair was ineffective and said he called his successor Gordon Brown “mad, bad, dangerous and beyond redemption”.

Earlier this year, he said the book would “ruffle some feathers”.

Lord Mandelson has been a controversial figure for years, having acquired the nickname ‘the Prince of Darkness’.

He was twice forced to resign from the Cabinet during Mr Blair’s premiership over his business dealings but returned to politics in 2008 to accept a seat in the Lords and become deputy prime minister in all but name.

His sexuality hit the headlines in 1998, when gay journalist Matthew Parris mentioned it on Newsnight.

Two years later, he allowed himself to be photographed in public with his long-term partner Reinaldo Avila da Silva.