Now the Treasury warns on HS2 costs and says high-speed rail link could be scrapped if price continues to rise Top civil servant warns there is no 'blank cheque' for controversial rail plan George Osborne has insisted HS2 will go ahead Costs have soared to £50billion, not counting VAT The High Speed Rail project could still be scrapped if costs continue to soar, the Treasury's top civil servant has warned. The government has not signed a "blank cheque" for the railway line linking the capital to the Midlands and North, Nick Macpherson, the permanent secretary at the Treasury told MPs. His words are in contrast to Chancellor George Osborne's insistence just two days ago that HS2 would go ahead. Mr Macpherson was echoing the promise made by shadow chancellor Ed Balls, that there would be "no blank cheque" for the line if Labour was in power - although the opposition has stopped short of announcing it would stop HS2. Controversial: The cost of the high-speed rail line HS2 may cause the project's demise Ministers are under pressure over burgeoning costs, which have soared from around £30 billion to more than £50 billion, not counting VAT. Mr Macpherson told MPs on the Treasury select committee: "If problems emerge we are not going to tinker around the edges. There will be a lot of opportunities for the government to review the policy. He added: "The expenditure, most of it happens way into the future. The big financial risks are also quite a long time into the future. There will be opportunities to reassess it. We have not signed a blank cheque. On Sunday, the Chancellor vowed the link to Manchester and Birmingham would go ahead, despite fears over soaring costs. Opposition: People living near the proposed route are furious about the plans Mr Osborne played down warnings the costs would overrun, saying: "We have set the budget for £42bn for the construction costs. His remarks showed a more upbeat view than Mr Macpherson, who answered a question about the project while discussing the Treasury's annual accounts. Building of the line is due to begin in 2017. Trains will run at 225mph from London to Birmingham by 2026 and onto Manchester and Leeds by 2032-3. HS2 is opposed by many Conservative MPs and their constituents as it cuts through the Chilterns, an area of outstanding natural beauty. Residents along the proposed route are furious that many have been unable to sell their homes. Property values have been blighted near the line and the government is planning to offer compensation. Investment: The revelation that Treasury insiders are against HS2 will reinforce doubts over whether it will go ahead Around half a million people are expected to be affected by the lengthy building of HS2. Even those nowhere near the line could find noisy lorries rumbling through their peaceful villages for years, according to the Campaign for Rural England. Business leaders have warned that it could be a giant "folly" while former Chancellor Alistair Darling - who initially supported the projected - warned it could become a "nightmare." Cheryl Gillan, a former Cabinet Minister whose constituency would be crossed by HS2, has said there are "better ways of spending £50 billion to £80 billion." Other critics have warned by the time the line is built, the rolling stock would be outdated and trains would be able to go faster. They have also queried why building on the line is beginning from London and the south, if the aim is to provide better transport links for those who live in the North of England. But other politicians are backing the project. Former Lib Dem leader Sir Menzies Campbell has said the country would "simply freeze up" without investment into major projects such as HS2. Tessa Jowell, the former Labour Culture Secretary, has also argued the economic and capacity case is "very strong" for HS2 to go ahead.