The government should also cut stamp duty, a land tax levied on property transactions.
Over the long term the burden has risen, which is one reason why the rate of transactions has slumped.
Abolishing or replacing stamp duty would help more young families live in decent homes.
Oldies could downsize at less cost, freeing up more of Britain's 25m or so empty bedrooms.
And Westminster needs to do away with the perverse incentives arising from local-government taxation, in particular the out-of-date system of council tax, which is levied on housing.
Councils miss out on much of the extra local tax revenue from new houses, because it is hoovered up and redistributed by central government.
But they are lumbered with the cost of providing local services for newcomers.
That should change.
Councils should be allowed to charge taxes that reflect the true values of properties—and keep the proceeds.
Economically straightforward is not the same as politically easy.
Even so, Theresa May, the prime minister, has so far failed to show any mettle over housing.
Her government has proposed nothing more than tweaks to a broken system.
This lack of leadership feeds a crisis that is entirely unnecessary.