Aerial view of a dam and a multi-level fish pass.Credit: Tom Maddick / SWNS

MORE than £130million has been spent on a handful of animal crossings across the UK — including £12million on a “fish motorway”.

The to protect wildlife including bats, snakes and deer from roads, railways and rivers.

But William Yarwood, of campaigners The TaxPayers’ Alliance, said: “These sums expose why UK infrastructure projects are among the most expensive and delayed in the world.

“Environmental mitigation has turned road and rail upgrades into financial black holes.”

The 200m Colwick (Holme Sluices) fish pass has been operational since 2024 in Nottingham.

But no formal monitoring has taken place — raising doubts over its effectiveness.

The Environment Agency installed it to help salmon and other migratory species navigate the Colwick flood defences on the River Trent.

Dr Scott McKenzie, of the Trent Rivers Trust, praised the scheme.

But he added: “Without a robust monitoring regime, we will remain in the dark.”

One local wrote online: “All it’s done is serve fish up as dinner to hordes of cormorants.”

Thesaid: “Monitoring will begin during migration periods this autumn.”

Elsewhere, a “bat tunnel” for in Buckinghamshire will cost £114million, while “green bridges” are being built over the A3 at Cobham, Surrey, and the A30 in Cornwall.