Lord Berkeley, deputy chairman of a panel reviewing the project, said Parliament has been misled about the price tag and predicted it would more than double to £107billion.
The future of the high-speed rail route between London and northern England has been hanging in the balance since Boris Johnson ordered a probe into its benefits.
But Lord Berkeley pulled his support for the Oakervee Review after rejecting its draft findings.
The peer published his damning report that claimed it would be poor value for money, bad for the environment and would fail to boost economic growth outside London.
Initial estimates put the cost of the project at £50.1billion but HS2 Ltd, the private company running it, has since pushed that up to £88billion.
Lord Berkeley claimed that independent analysis found the true cost will be more than £107billion.
He said: “I believe Parliament has been misled because the costs were clearly known to the department, and I believe ministers, three or four years ago – there’s a lot of evidence to that.
“My report suggests the project is completely out of control financially. It doesn’t benefit the North and the Midlands in the way that upgrading existing lines could.”
He added: “And they fiddled the figures to improve the benefit-cost ratio by allowing for 18 trains an hour to go on the line when nobody in the world runs more than 14. So the revenue is all shot to pieces.”
Phase one of HS2 was planned to run between London and Birmingham from 2026, but could be pushed back until 2031. Lord Berkeley said high-speed trains will not reach Manchester and Leeds until 2040.
HS2 Ltd said it was ready to start if the Government gives the go-ahead.
A spokesman said the line was vital for the UK’s low-carbon future. He added: “It will provide much-needed rail capacity up and down the country, and is integral to rail projects in the North and Midlands which will help rebalance the UK economy.”