“But what do you really think?”

That question will dog Gordon Brown for the rest of the election campaign – perhaps for the rest of his political career.

This was the day the prime minister was caught facing two ways – expressing one view in public and quite a different one in private.

The picture of Gordon Brown listening as the private became very, very public on BBC Radio 2 said it all.

Mr Brown sat in front of the microphone, leaning heavily on an elbow, head in his hand, as he heard the recording of his own voice describing lifelong Labour voter Gillian Duffy as a “bigoted woman”.

Dejection

His body language spoke of utter dejection.

It was a disastrous day for the prime minister’s election campaign – and in this instant he clearly knew it.

For the past three weeks Mr Brown’s team have been desperate to talk about substance, accusing us – the media travelling with him – of unfairly focusing on style.

But the affair of Gillian Duffy has both substance and style.

Eyewitness: Brown's 'disastrous day' after bigot slur