Gordon Brown has been caught unawares calling a Labour-supporting pensioner who confronted him on the election campaign trail a "bigot".
Gillian Duffy, a 66-year-old widow, told the Prime Minister that she was concerned about immigration from Eastern Europe.
Mr Brown chatted to her for five minutes and appeared to end the conversation amicably, telling her she came from a "good family".
But he was unaware that his microphone was still on as he got into his car and sped away, and was heard berating his staff for allowing the encounter.
He told an aide: "That was a disaster. Should never have put me with that woman. Whose idea was that?"
When the aide said they did not know who was responsible, the Prime Minister snapped: "ridiculous".
His companion suggested that television crews who filmed the encounter, in a residential street in Rochdale, would not broadcast it.
But Mr Brown said: "They will use it."
The aide asked what Mrs Duffy had said, and Mr Brown replied: "Everything. She's just a sort of bigoted woman who says she used to be Labour."