Fifty-seven per cent of Conservative members want the £56 billion railway project to be abandoned

Failure to build HS2 would be a “disaster” for the economy in the Midlands and north of England, the Treasury has been told.

As a poll reveals that a majority of Tory members want the high-speed rail line cancelled, local government and business leaders have warned that any decision to scrap it would undermine Britain’s “national prosperity for decades to come”.

In a letter to Liz Truss, chief secretary to the Treasury, more than 20 key figures from across the north and Midlands, including Andy Street, who as mayor of the West Midlands is the Conservative Party’s most senior directly-elected politician, insisted that the project was already attracting investment and cautioned against any attempt to halt the scheme.

The letter — delivered on Friday