Thursday 15 September 2016 5:55 pm

A senior Tory has issued a stinging slapdown to the government on the analyses behind HS2 and airport expansion

The Conservative chair of the highly influential Treasury Select Committee has questioned the government's evidence for decisions on both High Speed 2 and airport expansion, demanding publication of data backing the projects.

Andrew Tyrie wrote a furious letter to transport secretary Chris Grayling earlier this week, noting it would be the fifth time he had posed questions on the economic case to support the Davis Commission conclusion of a new runway at Heathrow.

“Failure to answer them will lead people either to conclude that this work has not been done – in which case it would be unacceptable for a decision to be made without the evidence to support it – or that it has been done, and gives answers that do not necessarily support the conclusions of the Davis report,” he wrote.

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And on HS2, the Treasury Committee chair said that while government support for the project is couched in terms of an economic case, “the numbers do not support such an argument”.

“HS2 has the weakest economic case of all the projects within the infrastructure programme, yet it is being pushed through the with the most enthusiasm,” Tyrie said.

“The case for providing sufficient detail to enable other ways of improving rail capacity – including at lower speed – to be fully assessed, remains very strong.”

The department for transport did not respond to request for comment.