The boss of the HS2 rail project has admitted the budget has doubled in five years, calling the increase in costs “terrible news”.The expected cost of completing the high-speed railway is now between £87.7 billion and £102.7 billion in 2025 prices, the government announced on Tuesday – almost £60bn more than originally expected.Chief executive Mark Wild told the Transport Select Committee on Wednesday: “Let’s just acknowledge this is terrible news, and we have to really think about the reasons for that.”The new target opening schedule for HS2 is between May 2036 and October 2039, 13 years later than planned.Mr Wild told MPs he is “very confident that these bookends of time and cost are robust”.The transport secretary also announced that HS2 trains will run slower than planned to save money (PA Wire)Transport secretary Heidi Alexander also revealed yesterday that trains will run slower than planned, with the maximum speed of services being 320kmh (199mph), down from the original design of 360kmh (224mph).Earlier this year, it was reported that HS2 bosses would explore the possibility of making the trains slower as ministers consider ways to cut spiralling costs on the embattled scheme, in a move branded “unwise” by unions.Ms Alexander said the cost increase was mostly because of “past misunderstanding of the work required, underestimation and inefficiency, issues within the control of HS2 Ltd, some of its suppliers, and previous governments”.She told MPs in the Commons she was “angry” about the “obscene increase in time and costs”, which she blamed on “the failures of successive Conservative governments”.Heidi Alexander said she was ‘angry’ about the ‘obscene increase in time and costs’ (PA Wire)Constructing the line from London to Birmingham – including the now-abandoned onward legs to Leeds and Manchester scrapped by the Conservatives, as first revealed by The Independent – was initially estimated to cost £32.7bn in 2011 prices, but the budget has spiralled.Mr Wild also pleaded with ministers last week not to cancel the project altogether in an extraordinary letter to the government.In a letter sent on Friday and published on Tuesday, he said the cost of cancellation and remediation works to areas where building has already started could range from £33bn to as high as £58bn.“Cancelling a programme of the scale of HS2 is unprecedented in the Western world. Accurate estimates are impossible to benchmark,” he wrote.He said removing the assets already built could be “more complex”, as the structures “are designed to last for 120 years and not to be dismantled”.The new target opening schedule for HS2 is between May 2036 and October 2039 (PA)Reacting to the increase in project time and costs, former Tory minister Sir Gavin Williamson, whose Staffordshire constituency has been heavily impacted by work on the line, said: "The cost and lack of control of HS2 is having an enormous impact not just on my constituents in terms of disruption but in terms of the pockets of everyone in this country."This is a busted project that has caused misery and just needs to be brought to a close as quickly as possible."Ms Alexander said the overall budget includes work at Euston, but the government was still seeking a private investor for the site.Last year, Ms Alexander told the Commons she was drawing a “line in the sand” over the project, which she described as an “appalling mess”.