It was the day that the great unspoken issue of the election – immigration – exploded in Gordon Brown’s face.

What should have been a routine encounter with a Labour-supporting grandmother turned into an unmitigated disaster for the PM.

Seconds after telling her she was a ‘good woman’, Mr Brown was caught by a TV microphone privately attacking Gillian Duffy, 66, as a ‘bigot’ for daring to raise immigration with him – laying bare his contempt for the concerns of millions of voters.

It came on the day that Labour’s favourite think-tank admitted those concerned about mass immigration had been treated as ‘nasty, stupid and backward.

Polls suggest the issue is second only to the economy among people’s concerns at the election, though none of the three main parties has been keen to discuss it.

Last night, despite an extraordinary 40-minute visit by Mr Brown to Mrs Duffy’s home to try to undo the damage, her niece, also called Gillian, said: ‘She’s a very strong-willed person and I don’t think she’ll accept the apology.’

In a tumultuous day that could deliver a knockout blow to his election hopes, the Prime Minister tore up his plans and returned to Mrs Duffy’s terrace house to beg for forgiveness.

He also tried to draw a line under the affair by sending a grovelling email to Labour supporters apologising for hurting the party’s campaign.

‘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,’ he wrote.

But his gaffe prompted anger among colleagues, who feared he had given voters a devastating insight into his own character and undermined the party’s stance on a key issue.

Mr Brown held his head in his hands as a recording of his off-guard remarks, made to an aide in the back of his limousine, was played back to him soon afterwards.

A shocked Mrs Duffy, a widow who spent her career working with handicapped children, said she had been a lifelong Labour supporter but would not now vote for Mr Brown.

Lord Mandelson led a desperate damage limitation exercise, pleading that the Prime Minister was ‘slightly tired’ and ‘letting off steam’ but admitting there could be ‘no justification’ for his remarks.

Spin doctor Alastair Campbell, who was last night helping Mr Brown prepare for tonight’s make-or-break leaders’ TV debate, admitted: ‘I don’t think I have ever seen him so angry with himself.’

The disaster – dubbed ‘Bigotgate’ in Westminster – unfolded as Mr Brown visited a community payback scheme in Rochdale.

Source: dailymail.co.uk