Economists are warning that the Chancellor's surprise reform of stamp duty could push up house prices.
George Osborne is replacing the old system of a few big jumps with gradual, tapered rises. He says that overall 98 per cent of homebuyers will pay less in future.
Business Editor Joel Hills has been finding out how it will work.
The Chancellor must tell voters whether what he's proposing is really a re-think of the role of the state.
For all the criticism of spending reductions under the Coalition, there are actually more cuts to come after 2015.
Could what seems like a lifeline for buyers - the overhaul of the unpopular stamp duty - actually make it harder to land a property?