The opening of HS2 will be delayed beyond the target date of 2033, the BBC understands.
Transport Secretary Heidi Alexander is expected to tell Parliament on Wednesday that there is “no reasonable way to deliver” the railway line on schedule and within budget – but is not expected to say how long the delay will be.
She is set to outline the findings of two reviews into HS2, one of which a “litany of failure” has been blamed for ballooning costs.
It is the latest setback for the high-speed rail project, which has been scaled back and delayed repeatedly.
Alexander is expected to say that Conservative governments presided over the cost of HS2 rising by £37bn between 2012, when the line was first approved, and the general election last year.
Under the original plans, HS2 was intended to create high-speed rail links between London and major cities in the Midlands and North of England.
It was designed to cut journey times and expand capacity on the railways, but has faced a myriad challenges and soaring costs.
It has already been pared down to a high-speed link between Birmingham and London, with the Birmingham to Manchester leg cancelled in 2023 due to costs getting “totally out of control”, the then-Chancellor Jeremy Hunt said.
That was two years after a planned eastern leg between Birmingham and Leeds was also axed.
Alexander is to release the two reports into HS2 in a bid to “draw a line in the sand” and mark a government reset in how major infrastructure is delivered.
One report will detail the findings of a review conducted by the former chief executive of Crossrail, James Stewart, which was commissioned last year to “investigate the oversight of major transport infrastructure projects”.
It is expected to set out what has gone wrong with the HS2 to date and what ministers can learn for future projects.
A second review by Mark Wild, the chief executive of HS2 who was put in place as part of efforts to get control of rising costs in October last year, will assess the construction of the project’s phase from London to Birmingham.
Last year, the Department for Transport said the remaining project cost was estimated at between £45bn and £54bn in 2019 prices – but HS2 management has estimated it could be as high as £57bn.
In 2010, it was estimated HS2 would cost £33bn and open in 2026.
Alexander is also expected to announce the appointment of Mike Brown, the former commissioner of Transport for London to become the new chair of HS2 Ltd.
