The Taxpayers' Alliance says more coaches should be way forward rather than the HS2 rail link, which would speed up journeys between London and the North.
Matthew Sinclair, Chief Executive of the TaxPayers' Alliance, said:
"As the projected costs have increased dramatically, the already fragile case for HS2 has completely disintegrated.
"There are far cheaper and better ways of substantially increasing capacity much more quickly on the route, not least by reducing the number of first class carriages and lengthening the trains."
More top news
Ryan King from Glossop was set upon in Hilton Street in the early hours of Sunday morning after leaving Pen and Pencil bar
Public urged to use NHS hospital services responsibly ahead of industrial action by junior doctors planned for Wednesday
A new report says Fab Four heritage has added more than 80 million to Liverpool's economy.