TV naturalist Chris Packham has urged people in Norfolk to join protest action against plans for the £198m Norwich Western Link road.
Extinction Rebellion Norwich, Friends of the Earth Norwich and other organisations will hold the 'Witness the Wensum' event on part of the route of the mooted road on Saturday, January 29.
And Mr Packham, who has been filming the BBC's Winterwatch at Old Ken Hill in Norfolk, has called for people to attend the event.
He tweeted: "C'mon Norfolk... let's get this project binned! If you're in the area this Saturday and have a bit of time, get on down.
"We don't need more road projects that only serve to drive up private car use - invest in green transport solutions instead."
Mr Packham was one of the signatories to a recent open letter against Norfolk County Council's proposed 3.9 mile road, along with Stephen Fry plus current and former MPs Clive Lewis and Norman Lamb.
Conservative-controlled Norfolk County Council has submitted a business case for the government to pay £168m towards the cost of the road, which would connect the A1067 near the Northern Distributor Road to the A47 near Easton.
Council leaders say the scheme, which would cross the River Wensum on a viaduct, will cut congestion and boost businesses.
Two petitions over the road have been set up. Gary Blundell, a town councillor in Costessey created one up in support of the road last week. It had been signed by 2,600 as Tuesday (January 25) afternoon.
One set up by the Stop The Wensum Link group two years ago has more than 6,200 signatures.
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