Highways bosses are confident controversial bat bridges along the Norwich Northern Distributor Road will help the mammals – despite a study suggesting similar structures on the A11 failed to do so.

Seven bat gantries are to be built along the £178.5m NDR, which will stretch from the A47 at Postwick to the A1067 Fakenham Road.

Designed to help bats cross roads, the bridges feature wire mesh strung high over the carriageway between two poles.

They are intended to replicate removed hedgerows and trees, giving the bat a reference point for sonar, so they avoid roads.

But a study last year into £350,000 bridges on the A11 concluded those gantries were not effective in guiding bats safely over the road.

However, John Birchall, Norfolk County Council's community liaison officer for the NDR, said there was currently no consensus of expert opinion which would convince the council to ditch its bat gantry plans.

He said: 'We are confident that the way we are installing bat gantries gives them the best chance of success.

'They are being placed precisely where there are known foraging and community routes, are of the latest design and have been incorporated into wider landscape measures.'

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