Greedy developers could be forced to sell land to the state more cheaply under radical plans being considered by Labour.
The party is examining proposals to ban housing firms from hiking the price of land once it has planning permission.
It comes after the party looked at research showing the price of land can soar from £21,000 to £2.1million a hectare if it switched from farming to residential use.
Such a ban, restricting sale prices to the market value without planning permission, would apply specifically to private developers who sold land to a new-style English Sovereign Land Trust.
Under the idea being considered by Shadow Housing Secretary John Healey, the Trust would buy up large plots of agricultural and industrial land – with compulsory purchase if necessary.
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It would then work with houses to ensure homes are built on the land.
The state could sell on the land with increased value from planning permission, freeing up funds to buy more land still.
A source said: "There is huge scope for funds to be generated by acquiring land in advance of planning permission, and then securing the uplift when consent is given."
The idea is not yet Labour policy, but aides have compared it to the programme that built the ‘new towns’ after the Second World War.
Mr Healey said the scheme could pour funds into cheaper housing, "rather than letting private landowners benefit from this windfall gain – and making everyone else pay for it."
Labour would need to change the law the implement the plans, which party figures insist would pay for themselves.