The latest estimated price tag for the controversial Norwich Western Link will not be revealed until December, council bosses have confirmed.
The government has confirmed it will provide £213m towards the previous £251m cost of the 3.9-mile road, which would connect the Northern Distributor Road to the A47 west of Norwich.
But that £251m figure is based on an estimate from summer last year, with the bill having almost certainly risen since then, as a result of inflation.
Conservative-controlled Norfolk County Council's cabinet had been due to meet in November to receive an update on the road, including the revised cost estimate.
However, the government's announcement of funding - and the need for the cabinet to agree to lodge a planning application for the scheme with its own planning committee - means the latest estimate will now be revealed in December.
The council is likely to have to dip into reserves and to borrow millions to cover the full cost, although officers hope discussions with the government will secure more money.
READ MORE: Critics vow fight against Norwich Western Link will continue
When the government announced 70 road schemes - including the Western Link - were in line to benefit from the scrapping of HS2, it said "most" of those which get outline business case approval would get a 100pc contribution, rather than 85pc.
And Graham Plant, the council's cabinet member for highways, transport and infrastructure, said the door had been left open for the scheme to get more money.
He said: "The announcement gives us a commitment from central government to fund the majority of the cost of the project and will bring an anticipated £213m of national investment into the county, with the potential for the government contribution to be uplifted to cover even more of the costs."
But Steve Morphew, leader of the opposition Labour group, said: "We expect to see the true whole life cost of the scheme based on figures that reflect the full impact of inflation and what that will mean to front-line services.
"Even if government makes a commitment to fully fund a scheme the rapidly escalating costs and length of time it will take to build, the price is likely to be astronomical and unaffordable."
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