No one has ever improved on Michael Kinsley's definition of a gaffe, which is what happens when a politician accidentally tells the truth.
Gordon Brown's comments this morning, captured by a TV microphone that he didn't know he was wearing as he left a campaign appearance in Rochdale, conform to Kinsley's rule. Pulling away in his black sedan, the prime minister growled that his impromptu exchange with a retired widow named Gillian Duffy was a "disaster" and "ridiculous". When asked by an aide what went wrong, the prime minister responded, "she was just a sort of bigoted woman."
If you watch the video, Gillian Duffy certainly does sound xenophobic as she confronts Brown. "You can't say anything about the immigrants," she complains. "… All these eastern Europeans what are coming in, where are they flocking from?". (Eastern Europe, I should think.) Brown's response – that inward migration to the UK has been more or less matched by outward migration – was perfectly reasonable.