By BBC News Online political correspondent Nick Assinder

Tony Blair has entered the second week of the NHS crisis with a massive fall in his popularity.

According to a new poll, his standing with voters has plummeted 25% in the past nine months.

The survey also shows Health Secretary Alan Milburn is the most unpopular member of the cabinet, with only 22% saying they were satisfied with his performance.

Deputy prime minister John Prescott has also suffered badly, with a 33% fall in his popularity.

Meanwhile rehabilitated Peter Mandelson, now Northern Ireland secretary, has suddenly become popular with a 25% increase in his standing.

Voters were asked to declare whether they were satisfied or not with ministers' performance.

Biggest losers

Mr Milburn and Mr Prescott were the biggest losers as the only two ministers recording negative figures.

But with the exceptions of Foreign Secretary Robin Cook and Mr Mandelson, all the others saw their figures dropping over months since last May.

Labour leaders will take some comfort from the fact that Tory leader William Hague is the only other politician to score a negative satisfaction rating: minus 10%.

The figures, compiled by ICM for The Mirror newspaper, are seriously bad news for the government and particularly the prime minister.

They suggest that the gloss has finally come off the New Labour image and that, like virtually all previous governments, it is vulnerable to mid-term slump.

But they also signal that Mr Blair's personal popularity, which he has previously relied upon to pull the government out of difficulty, may be on the wane.

It would be foolish to read too much into one opinion poll and, as all politicians will tell you, they have been disastrously wrong in the past.

"The only poll that counts is the one where voters put crosses against names in the ballot boxes," they will declare.

Strength of feeling

But for a government that is so driven by focus groups and surveys of voters attitudes, this latest test of public opinion will prove traumatic.

Ministers have already been taken aback at the strength of feeling over the situation in the NHS.

Their private surveys are certainly telling them that voters, particularly Labour supporters, are feeling let down by the state of the health service and the government's apparent inability to get to grips with it.

By sticking to the previous Tory government's spending limits in a bid to woo Middle England, it was inevitable that there would be no huge boost to NHS spending under Labour.

But now, clearly spooked by the crisis and the effect it is having on his credibility, Mr Blair is trying to suggest he is throwing money at it.

The survey was carried out over last weekend and clearly indicates a slump in support as a result of the NHS crisis.

The service is always going to be a litmus test of a Labour government's intentions, and Mr Blair appears to have failed badly. But there is other bad news in the poll.

The slump in Mr Prescott's standing is undoubtedly a reaction to his perceived failure to have got to grips with the country's creaking transport system.

And even Chancellor Gordon Brown's standing has fallen by 6%, suggesting voters may be starting to worry about the economy as interest rates have begun to rise.

Reaping rewards

Home Secretary Jack Straw has also seen a fall in popularity of 10%, which may be a result of his handling of sensitive issues like the Pinochet extradition and the Tyson affair.

Mr Mandelson's popularity boost is probably the result of him reaping the rewards for the Northern Ireland peace process.

So the dissatisfaction clearly goes beyond the NHS and covers many of the key areas of government policy.

This underlying slide in voter satisfaction will be deeply worrying for the government, which probably has around a year to go until Mr Blair decides to call the next general election.

It is clear that he and his government are still extremely popular with voters and, if that election were tomorrow, would stand every chance of romping to victory.

But these figures have shown they are not untouchable and will lead to some heart-searching in Downing Street.