Plans to build six bat “bridges” as part the A11 dualling scheme have been criticised by a Tory peer as a waste of money.

Baron Marlesford spoke out following a question he raised in the House of Lords earlier this month which revealed almost �500,000 had been spent on five bat bridges across the country since 2008.

A further six constructions are to be built as part of a Highways Agency scheme to widen the final nine miles of single-carriageway between Thetford and Barton Mills.

Lord Marlesford said although the decision was based on European legislation, “common sense” was needed at a time when government finances were constrained.

“I feel very strongly about public money at a time when we’re having to cut a lot of public spending,” he said.

“In the context of costs you need to say you will help bats, but there’s a limit. It’s a judgment which has been made at a time when some cancer patients, for example, are being told they can’t have the right drugs.

“I understand approval for the bridge at Thetford was given by the secretary of state, but I’m told they don’t know the cost and I find it astonishing they could approve it without knowing that. If they say it’s part of the cost of the road, I would say they’re wasting taxpayers’ money.”

The bridges aim to guide bats across the road and reduce the risk of them being killed or injured by a vehicle, by installing a telegraph pole on either side of the road with wires and mesh strung between.

A spokesman for the Highways Agency said it was “legally bound” to protect endangered species such as bats, and added the cost was included in the overall scheme.