IT IS rather late in the day for housing to become a political priority. More than a decade ago, a government-commissioned review by Kate Barker, an economist, said Britain needed much more building to keep up with demand. That did not happen. Today, politicians are grasping for policies that alleviate the resulting pain. Britons are obsessed with home ownership, but the shortage has put it out of the reach of many. In 2011, the census recorded the first fall in owner-occupation for more than half a century. The Conservative manifesto, launched on April 14th, borrows a policy from the past with the aim of arresting this trend and breaking the electoral deadlock.

In 1980 Margaret Thatcher’s Conservative government shook up the housing market by giving local council tenants the right to buy their homes at generous discounts. Since then, some 1.9m households have taken advantage of the offer, helping to drive up the home-ownership rate from 55% in 1979 to a peak of nearly 70% in 2001. Many credit the policy with creating a new horde of home-owning Tory voters and securing 18 years of continuous government for the party.

Mr Cameron now hopes to summon a bit of this Thatcherite magic. Unveiling their manifesto today Tories promise that if returned to power, they will extend right-to-buy to the 1.3 million Brits who rent from housing associations (private but non-profit bodies which provide social housing). Forcing associations to sell could prove legally tricky, but the government will pay for the discount.

The primary effect of right to buy—Thatcherite or Cameroon—is to transfer wealth from the taxpayer to the buyer. That might be desirable; those who benefit are not society’s poorest, but are not well-off, either. And there is ample evidence that the permanence of homeownership causes residents to invest more in their communities. Yet critics of right-to-buy have long lamented the erosion of Britain’s stock of social housing which it has caused.

Selling off houses cannot be blamed for an overall shortage—the total number of homes in the country remains the same—but it can force councils to pay the private sector to house those in need. That pushes up the housing benefit bill. And right-to-buy might reduce incentives to build anew, given the likelihood that new property will be sold off on the cheap. In the 1980s new council builds “pretty much disappeared” after right-to-buy was introduced, according to the Institute for Fiscal Studies, a think-tank. Housing associations claim that being forced to sell assets under the Tory plan will blunt their incentives to build, too.

Not so, say the Tories, who promise to build a new home to replace every one sold. They will fund both the giveaway and the replacement by forcing councils to sell off their highest value properties when they become vacant. If successful, the policy would increase the overall stock of housing, alleviating some of the shortage.

But the track record here is not good. The National Housing Federation (NHF), a group representing housing associations, points out that only 345,000 council homes have been built to replace the 1.9m sold-off since 1980. The NHF worries about fairness, too. The potential beneficiaries are already housed in decent and cheap homes; by contrast, the 3m adults who live with their parents, and those struggling to rent in the private sector, are not helped at all by the policy.

Yet the Tories know the potential potency of their pledge. The votes of 1.3 million housing association tenants are juicy bait, and those who will miss out from the giveaway are unlikely to notice much. The policy is unlikely to secure 18 years for Mr Cameron, but he hopes it might just win him another five.