Cost of HS2 ‘bat tunnel’ 20% higher than previously thought

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The final price tag for the notorious High Speed 2 bat tunnel is on track to be a fifth higher than previously thought, figures obtained by the Financial Times show.

HS2 chair Sir Jon Thompson told a rail industry conference in November that the conservation project would cost £100mn — a number that swiftly entered public consciousness.

Thompson’s estimate was based on the 2019 price of £95mn, figures obtained from HS2 by a Freedom of Information request show.

Adjusting for inflation, the sum would be £119mn in today’s prices, according to FT calculations. Additionally, the structure is not due to be completed until next year, meaning final costs could rise further with inflation.

As of January this year, around £65.5mn — in 2024 prices — has been spent on the kilometre-long steel mesh structure that is designed to protect bats from hitting the trains in the railway tunnel in Buckinghamshire, the figures also reveal.

The figures suggest there is still around £53.5mn to be spent on the project. But experts warned that the nature of public contracts mean that even if ministers cancelled the contract they would struggle to claw back all of the unspent money.

It would be too expensive to break the contracts despite the rising costs, said Noble Francis, economics director at the Construction Products Association, who added that it was essential that lessons were learned for future projects.

“Going forward, the government needs to ensure that issues like this are resolved well before construction on major infrastructure projects,” he said. “So many unnecessary, additional construction works like the bat tunnel are persistently done in mitigation, leading to even more increases in construction costs.”

The tunnel, designed to protect a colony of rare Bechstein’s bats, has become a totemic symbol of Britain’s onerous planning regime and the extreme cost overruns at HS2. 

Steve Reed, the environment secretary, told the FT it was “ludicrous” that taxpayers were spending “vast sums” on the bat tunnel.

“Regulations have held up the building of homes and infrastructure, blocking economic growth and doing little for nature,” he said.

“That is why we are introducing new planning reforms and a Nature Restoration Fund to unblock the building of homes and infrastructure and improve outcomes for our natural world.”

The Wildlife Trust, a charity, said that the government had ignored evidence provided to the high speed preparation bill more than a decade ago that highlighted cheaper, better alternatives to protect the bats in the area, which is a designated site of special scientific interest. 

This included a government decision not to conduct a “strategic environmental assessment”, a legal requirement to examine the wildlife impact of a plan or programme.

Becky Pullinger, head of land use planning at The Wildlife Trust, said the bat tunnel showed HS2 “adopted an engineering solution to an ecological problem and the law did not require this”. 

She added: “What the law requires is to avoid harm to bat populations, or indeed other protected species. In this case, this could have involved choosing a route which also avoided harm to a beautiful medieval hunting forest.”

HS2 Ltd said: “The demands of the UK planning and environmental consents process come at a high cost, largely out of HS2 Ltd’s control.”

The bat measure was just one of 8,276 consents HS2 needed from other public bodies to build the first phase of the rail link between London and Birmingham. The UK government has launched a major review into how to speed up planning procedures.

The cost of the entire railway between London and Birmingham continues to escalate and is now estimated at around £67bn and set to be revised upwards in the coming months. There is still no agreed plan or price tag for the high-speed railway line’s terminus at Euston station in central London.

Mark Wild, who was appointed chief executive of HS2 last year, has defended the bat tunnel, telling a committee of MPs earlier this year that he “can’t apologise” for the construction of the bat tunnel as it was the “most appropriate” way to “comply with the law”.

Asked whether he regretted the decision, Wild added: “It is an extraordinary amount of money but it is in the context of a scheme that is costing tens of billions and it’s built for 120 years.”

The 13 gramme Bechstein bat is one of the UK’s rarest mammals, and its population numbers have suffered an extensive decline because of habitat destruction, according to the Bat Conservation Trust.

The bat tunnel is being built by EKFB, a joint venture between engineering companies Eiffage, Kier, Ferrovial Construction and BAM Nuttall. EKFB declined to comment.