Council leaders insist they are "not selling off the countryside", even though some 200 acres of Norfolk farmland will be lost if a section of A47 dualling goes ahead.
Ninety-three acres of farmland owned by Norfolk County Council will be sold to allow the upgrading of the A47 between Blofield and North Burlingham, with National Highways using compulsory purchase powers to buy the land.
And a further 98.5 acres would be temporarily taken over during the work to dual the 1.6-mile stretch of road.
National Highways needs the land for the new carriageway, drainage, diversions and connections, including moving a gas main.
The land which is temporarily taken will be returned to the Conservative-controlled council once the work is done.
The council's agents have negotiated compensation with National Highways - the government's roads company, but the figure is being kept secret, with the authority citing commercial confidentiality.
The land is part of the County Farms estate, which is council-owned land rented to tenant farmers.
At a meeting of the council's cabinet where the sale was discussed, Jane James, County Hall cabinet member for corporate services and innovation, said it would not reduce the farms estate below the minimum 16,000 acres specified in the council's constitution.
She said: "Just to put people's minds at rest, that we are not selling off the countryside."
READ MORE: Norfolk A47 dualling decisions in hands of High Court judge
Whether the dualling, along with other A47 schemes at Thickthorn and between Easton and North Tuddenham, goes ahead hinges on the outcome of a High Court challenge launched by climate activist Andrew Boswell.
The cabinet also agreed to a deal for the Norfolk and Suffolk NHS Foundation Trust to rent two floors at County Hall at a cost of £320,000 a year.
And councillors also agreed to sell two patches of land it owns at the former Dersingham Infant School site.
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