E Jane Dickson: A goldfish government that can't recall anything

Cameron is not the only politician to suffer memory lapse. The fog is general all over Westminster

Has Cameron hit the manopause? The Prime Minister, in recent weeks, appears to be displaying classic symptoms more usually associated with les femmes d'un certain âge; the bursts of brick-faced temper, the sofa-bound lassitude, the woolly indecision. The diagnostic clincher, however, is the PM's apparent inability to remember things.

We've had the "Did I say that? Really?" U-turns on policy. We've had the "Oops, where did I leave my daughter?" moment. But the brain-fog hit crisis point at Leveson ( "Coulson? Splendid chap! Tell me again what he did...") and descended into a pantomime of "I'll forget my head, me!" forehead slapping. Cameron, we are expected to believe, had a dim memory of tipping up on Rupert Murdoch's yacht, but couldn't think why he was there. He might have discussed the BSkyB bid with Jeremy Hunt, but couldn't swear to it. Certainly, he'd bumped into Rebekah Brooks socially, but couldn't "recall the specifics". Maybe the best thing would be to call his wife.

Effectively, on anything touching his personal integrity, Cameron took the fifth. It got him, for now, out of a hole, but it's no way to run a government. Nor is he the only politician to suffer convenient memory-lapse. The fog is general all over Westminster. Gordon Brown even managed to raise amnesia to a moral virtue. Furious at The Sun for leaking the details of his son's illness, he nonetheless continued to court the editor in the spirit of forgiving and forgetting like the breezy insouciant we know him to be. Forgiveness has its place. Forgetting is really not so clever. Yet we find ourselves in an era of goldfish government, where policymakers look neither back nor forward, but rise with blithe expediency to the moment.

One minute, George Osborne is hectoring us on belt-tightening, the next he's manning the toffee cannon. The release this week of £140bn to high street banks is the latest in a string of screeching reverses. Sure, we've just spent two years slashing public services to the bone in the name of austerity, but, hey, tomorrow is another day and the polls aren't looking so good, so now we're going for growth! Increasingly, in his head-swivelling, "give me a sign" desperation, the Chancellor appears to be channelling Margaret Rutherford as Madame Arcati, Noël Coward's bogus medium. Osborne calls this "responsive government". ("The only thing worse than listening," he intones, bafflingly, "is not listening.") I'd call it a government swinging in the wind.

There is urgent need for a return to some kind of empiricism in politics, a realpolitik based not on expediency, but on evidence. The public can see what's going on around it, yet politicians swim round their bowl in a kind of solipsistic trance where "I don't remember" means "it didn't happen". It's the equivalent of toddlers screwing their eyes shut and hoping no one will see them.

Out in the real, evidential world, the poor are manifestly growing poorer. Food prices are rising and wages are falling. Local councils report a 14 per cent year-on-year increase in households in "priority need". The number of families forced by recession into bed and breakfast accommodation rose by 44 per cent. Two million children are living in households where the weekly income is less than £251 per week; that is to say, one in five British children is living, technically, in poverty.

These are the facts. But facts, it seems, are quickly "forgotten". Indeed, Work and Pensions Secretary Iain Duncan Smith appears to have forgotten – or, to put it more accurately, dismissed – the facts on the very same day they were issued by his own office.

On Thursday, he suggested that instead of dealing in numbers – nasty, intransigent things that they are – we should be dealing in values. Real poverty, he argues, eyes tightly shut, cannot be measured in money. A new metric for child poverty, taking into account factors such as parental drug addiction, worklessness, welfare dependency and family breakdown, is shortly to be revealed. You can't simply go by the figures, says IDS, because poverty since the 1970s has been defined as managing on an income below 60 per cent of the national median. Since that median has fallen in the recession, he concludes, the calculation isn't worth the envelope it's scribbled on.

If he were talking about average incomes, IDS might have a point. But median income – the halfway point between extremes – remains a useful measurement of relative wealth. It could be halfway between a billion and bugger all. If you're 40 per cent below it, you're still going to struggle.

No one is going to argue that parents on drugs or parents without work improve a child's life chances. Hungry children, however, are not on the whole pacified by political sophistry. In his crusade to redefine social ills as the cause rather than the symptom of poverty, Duncan Smith "forgets" that the children of the undeserving poor get every bit as hungry as their deserving peers. He also appears to forget that the Sure Start scheme axed by the Coalition delivered help precisely to those whose rackety situations he most deplores.

A government moved by evidence rather than by ideology would not give this "nothing to do with us, guv" shrug in the face of facts. (While we're at it, we might sort out the crucial difference between ideology and principle.)

There's more to policy than ducking flak. Some things, unpleasant to recall, cannot be forgotten. It's true that no one ever said a bad word about a goldfish. On the other hand, no one much cares when they're floating belly up.