For once, talk of a collapse in confidence is not an exaggeration. The new Populus poll for The Times makes awful reading for Gordon Brown. In September, when the Northern Rock affair erupted, voters were prepared to give Mr Brown and Alistair Darling the benefit of the doubt. Now, after the Revenue & Customs files debacle, they are not. What is worse, people have become more pessimistic about the economy.

Three caveats. First, the poll was a quickie, done on one evening, Wednesday. It is like measuring an earthquake as it is happening. The position will be different when the dust has settled. But there is still likely to be lasting damage to Mr Brown and Labour. Secondly, the poll was done online, in contrast to the usual telephone polls. But any difference should not affect the broad, very clear, trends (for more, see www.populus.co.uk).

Thirdly, a possible football effect. More than half the sample was done after England lost against Croatia, and they were distinctly gloomier about the economy (by 5 to 8 points) than those questioned before the match. There are parallels with the alleged impact of England’s defeat in the 1970 World Cup on Labour’s subsequent election loss.

Unlike many political events, the files row has had a big impact. Just 18 per cent dismiss it as a one-off incident, while 73 per cent say it has undermined their confidence in the Government’s ability to handle confidential data. Some 64 per cent say it calls into question “the basic competence of the Government”.

Gordon Brown's Black Wednesday

The Northern Rock disaster has torn away any remaining credibility the Prime Minister had

BACKGROUND

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• Gordon, how wonderful, wise and talented am I?

• Brown’s brain and his hand are not always connected

• How 'cruel' schooling scarred Brown

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• Voters' anger over data loss exposed in poll

The number viewing Labour as competent has fallen from 56 to 26 per cent in almost three months. While three fifths previously backed ID cards, 55 per cent now favour scrapping them, and just 29 per cent favour going ahead.

The number trusting the Brown-Darling team to handle any economic problems has more than halved from 61 per cent in early September to 28 per cent now. Trust in David Cameron and George Osborne has risen from 27 to 34 per cent, with neither/don’t knows jumping from 12 to 37 per cent. While the number regarding Labour as honest and principled has fallen from 37 to 20 per cent, the Tory rating is down from 34 to 26 per cent. This points to a broader disillusionment with all politicians.

But, crucially, the public has become more pessimistic about the economy. For more than four years, a clear majority believed that the economy would do well over the next year, both generally and for them and their families. But there has been a dramatic turnaround, with a clear majority now pessimistic. In March 56 per cent believed the economy would do well in the following year and 36 believed it would fare badly. In September the percentages were 53 to 45; now they have reversed to 34 to 55 per cent. This reflects not just the files fiasco, but also Northern Rock, the credit crunch, talk of falling house prices and an economic slowdown.

Mr Darling can console himself that, despite all this, just 44 per cent say he should lose his job, with 40 per cent behind him. But the row is not going to end quickly.

The problem is that, once a reputation for competence is lost, it is hard to regain. And if faith in economic stability, the pillar of Mr Brown’s standing, is shaken over the long term, then Labour is in deep, and possibly irreversible, trouble.

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