The proposed route of a controversial new road will have to be altered, but by how much remains a mystery for now.

Norfolk County Council has admitted it will have to alter the proposed route of the Norwich Western Link (NWL), due to bats being found in the vicinity of the current plan.

The scheme, to build a 3.9mile road that would connect the Northern Distributor Road (NDR) to the A47 west of Norwich, has been beset by problems in the last year, from rising costs to consultation delays.

The £198m project has been put forward by Norfolk County Council, which insists it will tackle rat-running and help cut overall carbon emissions from vehicles.

However, in a letter to a resident in the area, Martin Wilby, cabinet member for Highways, Transport and Infrastructure at County Hall, said: "A survey has identified notable bat activity in the woodlands in the area at the northern end of the proposed route which we need to take into account in our design.

"As a result, we're currently carrying out work to develop mitigation and refine the alignment to minimise the impact of the scheme on that area."

David Pett, from the Stop the Wensum Link group, criticised the time and money spent investigating routes.

"It is shocking and equally concerning to now hear an intention to realign the route," he said.

"If, as it seems, there is to be a significant shift in the path then the council needs to come clean and publish details of the new route."

Mr Pett branded the council's management "muddled and inept" and said it was unclear how the change will impact the outline business case (OBC).

But Mr Wilby insisted alterations are a normal part of the process for large-scale infrastructure projects.

He added: "Assessment and initial design work related to refining the alignment of the route and developing appropriate mitigation is underway and we’ll provide a further update on this work in a report to our cabinet in March.”

Asked how much the road plan has been altered and for the implications a spokeswoman for the council reiterated an update will be provided in March.

Last weekend, 300 people came out to protest the road. A petition supporting it has received more than 4,000 signatures, while one against has received almost 7,000.