Yesterday the government unveiled its housing strategy to "get the housing market moving again". The centrepiece was a mortgage indemnity scheme to help first-time buyers to get on the property ladder. But this policy is a disastrous waste of taxpayers' money that will satisfy nobody.

The mortgage indemnity scheme is set to make it possible for first-time buyers to borrow if they can find a deposit of just 5 per cent of the property value. Lenders, meanwhile, will offer the remaining 95 per cent, safe in the knowledge that the first 14 per cent of losses on a house that later sells for less than its initial price will be taken by either the buyer's deposit, or the taxpayer and house-builder's guarantees that cover the other 9 per cent. Whatever happened, you might ask, to the Government's mantra that "you can't get out of a debt crisis by taking on more debt"?

This is a bad deal for taxpayers. There are good reasons why lenders are currently unwilling to offer 95 per cent mortgages on the open market, and 90 per cent loans are rare. Mortgage providers are signalling that they expect prices to fall, and don't want to lose their money when they do. The current housing market very closely resembles a Ponzi scheme where new investors to the scheme (in this case first-time buyers) pay for the returns to existing members (higher house-prices for owners). As with all Ponzi schemes, this scam can't go on forever -- sooner or later you run out of unsuspecting new investors and the whole thing collapses. It's unfortunate, then, that the Government feels that it's wise to devote taxpayers' cash to one final round of pumping up the property bubble.

For similar reasons, the scheme is a false friend for first-time buyers. The current scarcity of highly leveraged loans for first-time buyers is a helpful signal to them to stay away from the precarious housing market. By meddling with those signals, the indemnity plan risks tempting hard-up young people into a falling housing market -- fodder for the last round of the Ponzi scheme.

Even business is likely to be disadvantaged by the scheme. With government offering attractive guarantees for residential mortgage lending, it would be unsurprising to see banks diverting funds away from vital lending to UK businesses in favour of unproductive property. This is the last thing we need in the current business lending drought.

Meanwhile, the real beneficiaries of the policy will be house-builders, who will be able to continue to sell over-priced property. But then there's always someone who benefits from a Ponzi scheme.

So at best, by buttressing house prices with taxpayer cash, this policy will be a simple transfer of wealth from young people without assets to older citizens with lots of housing wealth. At worst it will tempt vulnerable young buyers with little money into a falling market, wiping out their nest-eggs, and making the rest of us pay for it through our taxes.

Instead of this we need a real solution to the problem of unaffordable housing. House prices are high right now for two reasons: the emergency measures in place to deal with the credit crunch, and excessively restrictive planning laws. Rock-bottom interest rates are allowing existing home-owners to sustain huge mortgage debts -- for now. But this support for prices is temporary, simply postponing the day of reckoning when some owners will have to crystalise the losses on their over-priced properties. When that happens first-time buyers will find property much more affordable.

In the medium term, if we want our citizens to live in civilised conditions, the answer is to liberalise planning laws to allow house-builders to create homes where people actually want them. How often do you appreciate, say, the fallow scrub land of the green belt just south of Junction 26 on the M25? And now contrast this with how often you lament the absurd sums needed to afford that bigger house that would better suit your family's needs.

Until we recognise that these things are connected and have a level-headed discussion about the trade-offs, we will never be able to give our citizens the "dream of home-ownership" the Prime Minister aspires to, at a reasonable cost. But whatever your view on the long-term trade-off, one thing we should all agree on is that politicians should stay out of housing finance. It's time the government stopped trying to prop up the absurd UK property Ponzi scheme.

Ian Mulheirn is Director of the Social Market Foundation.