Gordon Brown apologised to Labour activists yesterday after he branded a pensioner a "bigot" while on the campaign trail.

The Prime Minister admitted that his unguarded comments about Gillian Duffy would make it more difficult for party supporters as the general election looms.

In an e-mail to Labour members, Mr Brown wrote: "As you may know, I have apologised to Mrs Duffy for remarks I made in the back of the car after meeting her on the campaign trail in Rochdale today. I would also like to apologise to you. I know how hard you all work to fight for me and the Labour Party, and to ensure we get our case over to the public.

"So when the mistake I made today has so dominated the news, doubtless with some impact on your own campaigning activities, I want you to know I doubly appreciate the efforts you make. Many of you know me personally. You know I have strengths as well as weaknesses. We all do. You also know that sometimes we say and do things we regret. I profoundly regret what I said this morning. I am under no illusions as to how much scorn some in the media will want to heap upon me in the days ahead."

But he insisted: "You will have seen me in one context on the TV today. I hope tomorrow you see once more someone not just proud to be your leader, but also someone who understands the economic challenges we face, how to meet them, and how that improves the lives of ordinary families all around Britain."

Mr Brown's campaign flew into a tailspin after he was forced to offer profuse apologies to Mrs Duffy, a widow in her 60s who had accosted him in the street in Rochdale.

After an apparently good-natured conversation on a range of hot political issues, Mr Brown said it had been "very good" to meet Mrs Duffy, before slipping into his prime ministerial Jaguar to be sped away.

But, having forgotten to remove his television microphone, his real thoughts about the encounter were recorded by broadcasters.

"That was a disaster - they should never have put me with that woman. Whose idea was that? It's Sue I think. It's just ridiculous," he told Justin Forsyth, his director of strategic communications.

Asked what she had said, Mr Brown added: "Everything, she was just a bigoted woman."

Mrs Duffy, a life-long Labour voter, had been entreated to speak directly to the Prime Minister as she stood heckling him on a visit to a community project.

Sue Nye, another senior aide to Mr Brown who has worked with him since the early 1990s, ensured the pensioner had the opportunity to confront him directly.

The move was typical of Labour's strategy in recent days of putting the Prime Minister in greater personal contact with ordinary people.