In a highly critical report published this morning, the Public Accounts Committee warned that there are still huge uncertainties over key areas of the project that threatened to continue to see costs soar.

The MPs said that the decision to axe the second phase of HS2 meant the project now offers very poor value for money to the taxpayer, and the Department and HS2 Ltd could not set out what the final benefits of the project would be.

The report warns that the Department of Transport must take a decision soon on funding the tunnelling from Old Oak Common to Euston to avoid incurring much greater costs from stopping and restarting work. 

It also raised concerns that the Government has failed to set out a plausible proposal on how its expects to attract private sector investment to deliver Euston station and the final tunnel drive from Old Oak Common.

The Government has redirected £6.5bn of expenditure away from Euston, and the Department of Transport is now looking for private funding to cover the costs of the re-scoped Euston station and the over-site development.

It recommended the Government must develop plans for a range of private investment scenarios, including different levels of public finance, as part of its consideration of how to progress with the station at Euston.

Dame Meg Hillier MP, Chair of the Committee, said: “The decision to cancel HS2’s Northern leg was a watershed moment that raises urgent and unanswered questions, laid out in our report.

“HS2 is the biggest ticket item by value on the Government’s books for infrastructure projects.

“As such, it was crying out for a steady hand at the tiller from the start.

“But, here we are after over a decade of our warnings on HS2’s management and spiralling costs – locked into the costly completion of a curtailed rump of a project and many unanswered questions and risks still attached to delivery of even this curtailed project.”

The MPs are also concerned about the uncertainty of the cost impact on the final project bill of the complex challenge of connecting HS2 to the West Coast Mainline.

A spokesperson for HS2 Ltd said: “We’ve been clear about our cost challenges, which have been compounded by significant levels of inflation.

“HS2 Ltd is now under new leadership and implementing changes across the programme aimed at controlling costs and learning the lessons of the past.”