The cost of the HS2 rail project could reach at least £80bn, almost double the current estimate, a report has found.
The study by the Institute for Economic Affairs (IEA) called for the project to be scrapped, saying it "defies economic logic", the Sunday Telegraph said.
In the report, to be published on Monday, the IEA says the cost of the scheme has been vastly underestimated, and argues that the £80bn price tag could deliver £320bn of value if spent on road and other rail and transport projects. Campaigners are also warn that more than half a million people across Middle England will have their lives affected by the project's construction.
HS2 has been launched to provide a 250mph rail link between London and Birmingham from 2026, with two further lines to Leeds and Manchester by 2032. But the IEA suggested that ministers were pushing the scheme through to "buy votes" in northern areas, said the newspaper.
The report suggested that the government's £42.6bn estimate would spiral because of a variety of factors, including changes to routes and extra tunnelling to placate opposition from campaigners; new stations and transport infrastructure around the proposed line; grants for regeneration to provide shops and amenities around the route; and compensation for towns and cities bypassed by the new line.
Dr Richard Wellings, the report's author, said it was "time the Government abandoned its plans to proceed with HS2", the Telegraph reported.
He said: "The evidence is now overwhelming that this will be unbelievably costly to the taxpayer while delivering incredibly poor value for money. It's shameful that, at a time of such financial difficulty for many families, the Government is caving in to lobbying from businesses, local councils and self-interested politicians more concerned with winning votes than governing in the national interest."
A spokesman for HS2 Ltd said: "While we respect the right of the IEA to state its case, their approach has clearly been designed to suit their aims and those of their funders to dismiss any major government project, something that they have consistently done over recent years.
"Government has set us a target cost of £17.16 billion for phase 1 of HS2 and we are focused on delivering within that target. HS2 is an engine for growth that provides significant value for money and will create a transformational national economic asset from which the whole of the UK will benefit for years to come."
A spokesman for the Department for Transport said: "HS2 is absolutely vital for this country, providing a huge economic boost which will generate a return on investment that will continue paying back for generations to come. The Government is committed to managing the cost within the budget we have set for the project and to securing maximum value for money for the taxpayer, while also ensuring that preparations are properly made for the most significant infrastructure investment the UK has seen in modern times.