By Ian Dunt
Gordon Brown has apologised to a widower after he was caught making disparaging comments about her on the campaign trail today.
He visited in her home this afternoon to apologise in person, after intense media pressure forced Labour to try to close down the row as quickly as possible.
Mr Brown had a short conversation with the 66-year-old while visiting earlier today, in which they discussed immigration and education among other matters.
But the prime minister appeared to forget he had an open mic on when he got back into his car.
Mr Brown could be heard to say: "That was a disaster.
"You should never have put me with that woman. Whose idea was that? It's just ridiculous.
When asked by an aide what she had said, the prime minister could be heard to reply: "Oh just everything. She was such a bigoted woman."
The gaffe played particularly badly when compared to Mr Brown's earlier behaviour towards the woman, which was warm and friendly.
Speaking outside her home to a frenzied scrum of reporters this afternoon, Mr Brown said: "I'm mortified by what's happened.
"I misunderstood what was said. She's accepted that and she's accepted my apology.
"I'm a penitent sinner. Once you use that word and made a mistake you should apologise."
Confronted with the tape during an interview on BBC Radio 2 just moments after he made the comments, the prime minister slouched in his chair with his head in his hand, cutting a beaten and dejected figure.
Gordon Brown during his Radio 2 interview
Peter Mandelson insisted the prime minister was very upset about the incident and said there was no justification for it.
Speaking to the press just moments after she was informed of Mr Brown's comments, Gillian Duffy, who used to be a Labour supporter, said she was "very disappointed".
"It's very upsetting. I'm very upset. He's an educated person, why is he coming up with words like that?" she said.
Speaking to Sky News, shadow chancellor George Osborne said: "We have found out the prime minister's internal thoughts. I think they speak for themselves and the prime minister has a lot of explaining to do.
"He certainly should apologise. The thing about general elections is they reveal the truth about people."
The Liberal Democrats said it was not their place to comment, although Nick Clegg said the prime minister was right to apologise.
Bookies immediately lengthened the odds of a Labour victory.
The governing party went from 4/1 to 5/1 following the incident, Paddy Power said.
William Hill quoted odds of 12/1 Mr Brown would resign as Labour leader before the general election, and lengthened his odds on winning Thursday's leaders' debate from 5/2 to 3/1.