HS2 is spending more than £100m on a "shed" to protect bats on a section of the line, even though there is "no evidence that high-speed trains interfere with bats", the project company's chairman has said.
Sir Jon Thompson said the 1km (0.6 mile) curved structure at Sheephouse Wood in Buckinghamshire will create a barrier so the creatures can fly over the railway without being affected by passing trains as all bats are legally protected in the UK.
He told the Rail Industry Association's annual conference in London on Thursday HS2 is calling the building "a shed", and it is being built to appease Whitehall advisory body, Natural England.
Sir Jon warned his audience they would not believe it, but the shed "cost more than £100m to protect the bats in this wood".
It was, he said, an example of the UK's "genuine problem" with completing major infrastructure projects, explaining that the government-owned company has had to obtain 8,276 consents from other public bodies related to planning, transport and the environment to build phase one of the railway between the capital and Birmingham.
He said: "People say you've gone over the budget, but did people think about the bats [when setting the budget]?
"I'm being trite about it but I'm trying to illustrate one example of the 8,276 of these [consents]."
Other, costlier options were also looked at while the High Speed Two (London to West Midlands) Act was going through parliament, he said, including boring a tunnel and re-routing the railway away from the wood.
Even after Natural England approved the design, the company had to spend "hundreds of thousands of pounds" on lawyers and environmental specialists because the local council did not approve the work, Sir Jon said.
"In the end, I won the planning permission by going above Buckinghamshire Council's head," he explained.
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Sir Jon, who has led the project since Mark Thurston left his role as chief executive in September 2023, warned in January that the estimated cost for phase one has soared to as much as £66.6bn.
In 2013, HS2 was estimated to cost £37.5bn (in 2009 prices) for the entire planned network, including now-scrapped extensions from Birmingham to both Manchester and Leeds.