Springwatch presenter Chris Packham has asked the people of East Anglia to "find some bravery" and say no to the controversial Western Link Road.
During a YouTube episode of his Self-Isolating Bird Club on Sunday morning, the naturalist derided the Norfolk project as an unjustifiable threat to the super colony of rare Barbastelle bats living in a woodland between Weston Longville and Ringland.
If approved, the Western Link would see the Norwich Distributor Road link up to the A47 to the west of Norwich.
Currently, the NDR stops at the A1067 Fakenham Road, but supporters of its extension include the N&N, Norfolk Chamber of Commerce, Norfolk Fire and Rescue, the New Anglia Local Enterprise Partnership and city and district councils.
Mr Packham, however, stands firmly among opposition ranks.
Speaking on his programme, Dr Lotty Packman, director of Wild Wings Ecology and associate at the University of East Anglia, said: "These bats can live for more than 20 years, which is incredible for such a small species.
"They are very site faithful and return here year after year to raise their pups."
She said that last summer her team had tagged the bats with tracking devices, and through that discovered they had maternity roosts in the Norwich woodland.
Cutting that woodland corridor in two would be disastrous for the colony, she added.
Building on Dr Packman's report, Mr Packham said that building the road would cause irreparable damage - and that the compensation offered by the developers would never be enough.
"The idea you can replace ancient woodland with 50cm saplings is nonsense", he said.
"We can't carry on building, building, building."
The presenter and naturalist then drew viewers' attention to a crowd funder, set up to acquire donations for legal advice and an ecological consultant for the "Stop the Wensum Link" campaign.
"I'm saying to East Anglia: find some bravery up there and say no to this development", he said.
His step daughter and co-presenter Megan McCubbin echoed him: "Get talking to your communities.
"Local elections are coming up next week. Remember to vote with the environment in mind."
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