That is according to the National Audit Office (NAO) in a report on the high-speed rail link between London, the West Midlands and the north of England published today (Friday, January 24).
Stop HS2 campaign manager Joe Rukin said: “It now is clear we have all lied to for years over the costs, timescales and benefits of this environmentally damaging project.
"We would say the scandal that is HS2 couldn’t get any worse than this, but we know it will.
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"This national embarrassment has to be cancelled immediately, and surely the only question now is deciding which are the projects that will be built instead of this terminal white elephant.”
Phase one of the Department for Transport's (DfT) the beleaguered scheme is due to go from London to Birmingham, with the line in Northamptonshire passing Brackley, Sulgrave, Chipping Warden and Upper Boddington.
HS2 was due to cost £56 billion in 2015 but that figure could now rise to £88 billion, according to the NAO, but there are fears it could eventually be even higher.
The report also says that in March 2019, HS2 Ltd formally advised DfT that it would not be able to deliver the first phase of the programme on time or within available funding.
Full services on the entire network are now forecast to start between 2036 and 2040, between three and seven years later than originally planned.
The NAO has made a series of recommendations covering the robustness of cost and schedule estimates, the capabilities needed to manage a programme of this scale and the oversight arrangements required for the remaining phases.
Gareth Davies, head of the NAO said: “There are important lessons to be learned from HS2, not only for the DfT and HS2 Ltd, but for other major infrastructure programmes.
"To ensure public trust, DfT and HS2 Ltd must be transparent and provide realistic assessments of costs and completion dates as the programme develops, recognising the many risks to the successful delivery of the railway that remain.”
A DfT spokesperson said: "The department has supported this review and is already acting on many of its recommendations.
"To ensure transparency around the project, we have worked closely with the NAO to provide information on the latest cost and schedule estimates for HS2.
"We recognise that there have been significant underestimations of both the cost and schedule of HS2 in the past, which is why we commissioned the Oakervee review to provide advice on whether and how to proceed with HS2."