The case for building the line has not been made, and even if it does get built the biggest beneficiary would be the capital, a worrying new report suggests.
The Department for Transport has been told to set out a better case for HS2 or risk rising opposition to the line planned as a key feature in efforts to rebalance the economy.
The House of Lords economic affairs committee said that if the line does go ahead it would be better if the Government started in the north and worked south, rather than the current plan to build the London to Birmingham link first.
Lord Hollick, chairman of the committee, said: “At £50bn HS2 will be one of the most expensive infrastructure projects ever undertaken in the UK but the Government have not yet made a convincing case for why it is necessary.”
He added: “London is likely to be the main beneficiary from HS2.
“Investment in improving rail links in the North of England might deliver much greater economic benefit at a fraction of the cost of HS2.”
The report is the latest in a series of blows to the High Speed project.
Last week Ukip leader said the scheme should be scrapped as a waste of money while shadow chancellor Ed Balls has repeated his “no blank cheque” warning to High Speed planners.
In its report, the committee said there was a strong case for improving the trans-Pennine links (the so-called HS3 option) or building the second phase of HS2 first.
Both of these options would be a better way of rebalancing the economy than constructing the London-Birmingham phase.
The peers also said that cutting the speed of the HS2 trains from 250mph to 200mph would reduce the cost, as would terminating the southern end of the line at Old Oak Common in north west London rather than at Euston.
Another way of completing the project for less money would be to learn lessons from France to reduce the cost of construction, the committee said.
The report concluded that overcrowding was largely a problem confined to Friday evenings and weekends on long-distance trains and to London-bound commuter trains.
The peers called on the Government to make a convincing case for the project before Parliament passed the HS2 Bill.
Keith Wakefield, leader of Leeds City Council, said he was “disappointed” that the committee had taken a negative stance on HS2.
He added: “There is compelling evidence, as outlined in the Higgins Report, that this much needed investment in transport infrastructure will not only play a key role in rebalancing the UK economy, but is also vital in unlocking the enormous potential in Leeds, the city region and across the North and Midlands.”
A Department for Transport spokesman said: “The case for HS2 is crystal clear. It will have a transformational effect, supporting growth in the North by improving connectivity, freeing up space on our crowded rail network, promoting regeneration, boosting local skills, generating tens of thousands of jobs and helping secure the UK’s future prosperity.
“It is a vital part of the Government’s long-term economic plan.”