Cameron will rue floods speech ...

You could call that a message of hope for people whose lives, homes and businesses have been devastated by incessant flooding. You could also call it rash, even irresponsible. The floods and gales might be horrible for those afflicted; they might be ruinous economically. The bill for infrastructure repairs will be vast. But the real human cost thus far amounts to the sad, apparently accidental deaths of a child and an elderly man.

That kind of tragedy is not what motivates Cameron, or what causes him to treat promises like cash in the bank. Would this same Tory politician have said that "money is no object" if it meant an end to, say, child poverty? Even as his ministers and officials worked frantically last week to explain that "whatever it takes" is no sort of blank cheque, the Prime Minister went on suggesting that every need would be met.

In the south of England, public misery has become public fury. Many of those enraged were Coalition supporters before the rains came. They are the kind of voters who have accepted austerity or actively approved of the Coalition's deficit reduction mania. Given the number of seats held by Tories and the LibDems in the south, we can assume that many of those placed under siege by the elements are not averse, philosophically, to smaller government. But they want Government action now, and plenty of it. Bluntly, Cameron has been trying to buy such people off.

Danny Alexander, Chief Secretary to the ­Treasury, was one of those obliged to pour cold water, so to speak, on the Prime Minister's seeming profligacy. The cost of a multitude of new road and rail schemes capable of withstanding the worst of the weather would have to be met, he said, from existing budgets. Elsewhere, departmental contingency funds will be raided for grants and compensation. Old money will be presented as new money. But the vice placed on spending by George Osborne and the Treasury will not be slackened.

Meanwhile, no-one in government is promising that redundancies within England's Environment Agency - by this October, 2830 jobs will have gone since 2009 - are to be reversed. Arguments over the amount spent or not spent on flood defences go on, but Cameron has failed to persuade those who believe that at least half a billion in funding is still needed, even in the unlikely event that this winter is not a taste of what might be to come. Contingency cash will not be available each and every year.

It is probably too early to say that the Prime Minister is deceiving people outright. He might yet scrape together enough money to be able at least to claim, as he said in the Commons last week, that no "penny-pinching" has been allowed. But his inflated language, his persistent assertion that every need will be met no matter what, falls well short of honesty. In January, just for the purposes of comparison, 133 claims for compensation arising out of the London riots in August 2011 had still not been met.

But why would Cameron risk misleading people? Why would the leader of a party committed to the belief that government cannot - and should not - attempt to do everything suddenly start talking like a cradle-to-grave socialist? Why not level with the voters of the English south? The Prime Minister could just say, honestly, that while it is the Government's job to keep the country running, it has no obligation to deliver sandbags to Mrs Smith's patio.

Cameron has been spooked by growing public anger: that much is plain. He might yet find that resentment over unmet promises will linger long after the flood waters have gone. Then he might have to deal with the fact that an electorate cynical towards politicians soon rediscovers a belief in interventionist government when there is a crisis on the doorstep. A shrunken state is the stuff of Westminster waffle. It wins precious few votes when the family home is being wrecked.

Cameron and Osborne have talked themselves into this test of faith. The idea that Government departments can "do more with less" might sit well with an arbitrary deficit reduction scheme. Doing more with fewer - trains, frontline workers, dredgers, pumps, sandbags - is an impossibility. For tens of thousands of people in the English south, meanwhile, there is nothing abstract about a worsening crisis. When the family photographs are floating around in raw sewage, disgust is as personal as it can be.

Even those politicians addicted to scepticism towards climate change - Tories in the main - have to deal with the fact that wild and unpredictable weather will alter attitudes towards the role of government. In this, the duty to be honest is becoming hard to evade. David Cameron did not personally flood the Thames Valley, but he is nonetheless, in another sense of the word, held responsible. He and his peers, in all parties, have yet to find the courage to contest this brutal judgment.

When do you tell dismayed householders that the rail network takes priority? When do you tell people, especially those outside urban centres, that the cost of flood protection is too high, that they are, and must be, on their own? When do you tell them the truth: that vast sums must be paid in taxes if everyone is to be protected, or much that is held dear - fields, houses, coastlines - must be sacrificed?

Ironically enough, it seems the sole ray of light to pierce the pelting rain has been the re-emergence of a sense of community in places left to their own devices. It probably counts as scant consolation when you and your neighbours are filling your own sandbags, but many responses to the weather's assaults have been the purest examples of what Cameron used to call "localism". It is a fact that he and Eric Pickles, the blustering Communities Minister, should bear in mind when next they decide to squeeze English council funding. Give aid to the self-reliant and you can save a lot of that scarce money.

The notion will become a cliché soon enough: for Cameron, these are the perfect storms. The anger of those fearing for inundated homes is a kind of shadow debate, full of deep passions, on the very role and purpose of government. People might dislike the nanny state, as the Prime Minister believes, but the state that leaves them defenceless, that offers no help or practical solidarity, soon becomes an object of derision.

The politicians who believe voters ask too much lack the courage to say so. The weather, seemingly relentless, certainly unstoppable, meanwhile pays no heed to bravado or promises. It destroys pretensions as easily as it destroys homes. For Cameron's kind, all the forecasts are bad.