Margaret Hodge MP, Chair of the Committee of Public Accounts, has said the economic justification for HS2 is "very questionable".
It comes as the Committee of Public Accounts issued a withering assessment of the HS2 high-speed rail project, warning costs were spiralling whilst benefits were dwindling.
The Transport Secretary, Patrick McLoughlin, said the case for the £50 billion project was "absolutely clear," as rail routes would be "overwhelmed" by rising passenger numbers.
An influential group of MPs says the DfT has failed to present 'a convincing strategic case' for HS2.
Campaigners say they hope to put plans for HS2 through the Midlands back to square one as they prepare to go to the High Court tomorrow.
Campaigners from HS2 Action Alliance are heading to London tomorrow to take on the Government at the Court of Appeal.