The mic remained live on Gordon Brown's lapel after his chat with Gillian Duffy
By Gary O'Donoghue
Political correspondent, BBC News
People often talk about political gaffes in terms of car crashes. But this is no car crash, this is a multi-lane, multi-vehicle pile-up of enormous proportion.
John Major's unguarded comments
about three members of his own cabinet being caught on mic, worse than George W Bush also being caught on mic describing a journalist in an unfavourable light.
And possibly even worse than John Prescott's instinctive reaction in thumping a protestor during the 2001 election campaign after he'd been hit by an egg.
So why is it so bad for Gordon Brown, now that he has been caught on mic, in his car, calling a member of the voting public a "bigoted woman" after a chat on camera in the street?
Even if you leave aside the fact that we're eight days from polling day, and the fact that Labour has been trailing third in a number of polls, the stark impression now for all to see is that Mr Brown is charm itself in public, and dismissive and insulting in private.
Situations like this are always difficult for politicians. You're confronted by a member of the public, the cameras are there, you have no idea who they are or what they're going to say.
Pleased to meet you
The irony is that Mr Brown had actually managed to talk Gillian Duffy round. She'd said she was planning to vote Labour at the end of their conversation and was satisfied with the prime minister's answers.
He'd inquired about her family, told her he was pleased to see her, chatted about her grandchildren and even said that she had a "good family".
So, what was Mrs Duffy's sin that allowed the PM to describe her as a "bigoted woman" once he thought he was out of ear-shot in the privacy of his own car?
She asked him how he planned to reduce the deficit; she asked him about her grandchildren's chances of going to university and how they'd pay for it; and she raised the question of immigration from Eastern Europe and what that could mean for jobs in her area.
Head hung low
In other words, not trivial, not irrelevant, but core political issues.
The prime minister's reaction on BBC Radio 2's Jeremy Vine programme said it all.
As the tape was played to him, presumably unaware that there were television cameras filming the radio interview, he held his head in his hands, highly emotional, conscious no doubt that this was a disaster of his own making.
Now the prime minister has apologised, he's spoken to Mrs Duffy and his chief lieutenant, Lord Mandelson, has hit the airwaves eating humble pie for his boss.
These things do of course fade with time, and there is a risk that their importance is overplayed. But Mrs Duffy and people like her are core to Labour staving off a meltdown at this election.
There is just a chance that Labour supporters may feel tempted to return the contempt with which Gordon Brown appears to have treated one voter.