An enforced change to the route of the controversial £198m Western Link has left serious question marks hanging over the entire scheme, campaigners have said.

Officers have been left scrambling to come up with an alternative for a section of the 3.8 mile route they came up with three years ago, after latest surveys confirmed the presence of bats roosting in woodland - something critics had long warned about.

County Hall has now announced new plans which would see some of the road redrawn and built further east than originally planned to avoid the habitat of barbastelle bats, a protected species.

The council says it is too soon to say how many millions more it would add to the road's price tag, and what sort of delay it would add to the project.

While officers are optimistic it will not scupper the bid for £169m from the government to bankroll the route, critics believe it could cast major doubts over the entire scheme.

Emma Corlett, deputy leader of the council's Labour group and an opponent of the road, said: "It's clear the presence of the bats pose a real threat to the whole project, as I, and others, have been warning since the start."

The Western Link is designed to connect the A1067 Fakenham Road to the A47 near Honingham. The section in question is to the north of the route and includes the stretch where a viaduct will cross the River Wensum.

The council first acknowledged it might have to move the route earlier this year, but has now officially revealed where and how it will have to be altered.

Martin Wilby, cabinet member for highways, infrastructure and transport, said he remained totally committed to the project and that this sort of issue was normal in such schemes.

He said: “There is strong support for the Western Link, as it will reduce journey times and emergency service response times, cut rat running through communities and boost our economy.

“We follow a very thorough process with major infrastructure projects and detailed ecological surveys, conducted by accredited experts, are part of this.

“In the light of the evidence gathered through our surveys, we are working with our contractors, Ferrovial and WSP, to refine the route.

“We have always said we would deliver the project in an environmentally responsible way and this is further evidence of that commitment."

A report into the need to refine the road's route will go before members of the Conservative-controlled cabinet on Monday, March 7.

That report says further details on costs and the impact on the timescale for the scheme will be presented in June after more work to firm up the amended route, which will involve talks with landowners.

Officers do not believe the changes would mean the business case for the scheme submitted to the government would have to be redone.

However, critics have called this into question.

They have long highlighted concerns over the presence of barbastelle bats in the area identified in surveys by Wild Wings Ecology and said the council should now scrap the road.

Ms Corlett said it was not standard that a scheme could get to such a point and then have to be realigned.

"There's some really major and fundamental questions which have not been answered," she added.

"There's no detail on the implications for the timescale or cost, but we know that for every month the project is delayed that's an extra £250,000 a month just in increased interest rates.

"Obviously, I think we should scrap it, but I hope those who do support the road should agree that it should now be paused and no more money poured down the drain until we have more information about the implications."

Ms Corlett said the latest developments should trigger an investigation into the way the project has been managed, but Mr Wilby insisted proper processes had been followed.

David Pett, from the Stop the Wensum Link campaign group, said: "It's astonishing that having spent vast sums of public money on choosing in 2019 a route for this proposed road we are told some three years and £20m pounds later, that new route options are now receiving consideration.

"This raises serious and far reaching questions about the council’s reputation and competency. This major set back can only spell disaster for this project.

"The time has come to admit defeat, to cut the losses and to begin urgent work on finding a Plan B."

Jamie Osborn, Green county councillor, said: "This further delay will push costs up, yet the council is refusing to be straight with the public and tell us how many more millions will be wasted.

"It is past time to end this folly and invest instead in effective and environmentally friendly alternatives."

But Clare Morton, chair of Weston Longville Parish Council, said: “The parish council welcomes the ongoing work being carried out by the council, which will ultimately ensure the smooth delivery of the Norwich Western Link.

"It is important that the council constantly reviews and refines their proposals as additional information comes to light, so as to ensure that any road solution produces the best possible outcomes.

“The new road offers the only option to relieve the parish of Weston Longville of its ever increasing burden of traffic.

"A new road to enable vehicles to easily cross the Wensum Valley has been a long time coming and the detailed work currently being undertaken will finally deliver a transport solution that addresses the many issues associated with the current unsuitable infrastructure."