Chancellor George Osborne has welcomed Sir David Higgins' recommendations for HS2, but warned there will be "no increases" in spending on the £50 billion poject.
Mr Osborne described the high-speed project as "essential to the future of this country".
However, he cautioned: "We must be conscious of the price, and there will be no increases to the overall spending envelope set for HS2 at the last spending review."
Earlier today, Shadow Transport Secretary Mary Creagh said there would be no "blank cheque" for the project.
Ms Creagh told BBC Radio 4's The World At One that Labour would be supporting the hybrid bill due to come before parliament but argued that the project had "suffered from mismanagement".