Just when I thought the government policy of cutting benefits (aka "reform") had reached its zenith of bizarre, unrealistic cruelty, along comes another cunning plan so ill considered it defies belief. The latest wheeze being floated is the suggestion that nobody under the age of 25 should be entitled to housing benefit.

The idea is so full of holes that the list of exemptions required to plug the gaps will be lengthy and ridiculous. Here are the problems: first, the glaringly obvious. What if claimants don't have a family to return to? There are extremes, such as when parents are dead, or have emigrated. Mummy and daddy might have thrown their offspring out on to the streets. They might have downsized into a one-bedroom flat.

That "child" might by now be a hulking great 24-year-old who has lived away from the parental home since the age of 16, possibly with a few children of their own, herded back to an area they left six years previously to find work, but where unemployment is high.

This plan also ignores social changes experienced by even the grandest of patrician Tories: the results of a second marriage are often more children, and so claimants might be refused access to their former bedroom, now occupied by a teenage half-sibling of the opposite sex. Such sharing leads to the overcrowding vociferously and rightly condemned by most councils, Shelter and notably, the government itself. There are also practical problems. Houses in the UK are notorious for being small in size – the smallest in Europe, in fact.

As for the claim that this will cut soaring benefit levels, remember, as has been pointed out elsewhere, that many claimants are actually working, albeit in low pay, or simply can't find enough hours to pay their living costs. Housing benefit in such cases is just another way to subsidise the low wages paid by certain companies, and is not a hand-out to feckless teenagers. According to Shelter, fewer than 163,000 childless, single young adults rely on housing benefit to keep a roof over their head.

And what about workless or disabled families on benefits with an under-25 living happily at home? What happens if their claim no longer covers their son or daughter? Is this unfortunate person to be forced out, moving into rented housing, where they would not, if workless, be entitled to housing benefit? It's surreal and perverse.

These announcements about soaring/rocketing housing benefit payments also omit one salient fact: housing benefit goes to buy-to-let landlords in the private sector, which is effectively another way of the state merrily showering welfare on businesses, while slashing payments to private individuals in dire need.

Policies like this will force young people (and 25 is not so young) to turn once more to the precarious support systems the welfare state was intended to bolster. Worst of all, this idea was first tried in 1988, when the Thatcher governments DWP flirted briefly, notoriously and unsuccessfully with abolishing income support and housing benefit to those under 18.

Officially, middle-age starts at 35, but the shared-room rate of housing benefit already forces anyone under that landmark into shared housing, which infantilises independent grown-ups. And remember the cost of moving belongings to the parental home, when those who have lived separately for many years will require relocation costs, like van hire. But the government has abolished the Social Fund. So claimants can't get a loan to pay for a van. And parents in social housing with a spare room will have been forced to move. So there is no spare room. And around we go.

Ideas like this have been described as "kite flying", where a policy is floated in the air, and usually shot down over a bank holiday. It will, I imagine be quietly dropped. This plan could only have been dreamed up by out-of-touch landowners who live in vast country estates, able to house returning adult children in a spare wing of their mansion. They can't be serious. Can they?

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