Demand for the HS2 high-speed rail project has "likely been overestimated" and the £33 billion project does not offer good value for money, according to a report by a think-tank.
Evidence that HS2 will promote economic growth or tackle the north-south divide is "limited", the report from the New Economics Foundation (NEF) said.
The line, whose first phase from London to Birmingham runs through picturesque Tory heartlands, will be "carbon intensive and environmentally damaging", the foundation added.
It was "time to invest in transport away from London" with the money earmarked for HS2 being "better spent elsewhere", the report said.
The NEF said: "Demand for HS2 has likely been overestimated by oversimplified government modelling."
The foundation suggested alternatives for the money that will be spent on HS2:
:: £10 billion - could transform rail infrastructure in northern England and the Midlands, creating new and faster east-west rail links, redeveloping stations and electrifying regional rail lines;
:: £10 billion - could overhaul the East and West Coast main lines, increasing the speed, capacity and reliability of north-south rail travel with less environmental damage than HS2;
:: £6 billion - could upgrade mass transport in Birmingham, Leeds, Manchester and Liverpool, including investments in large light rail schemes and bus networks;
:: £4.5 billion - could roll-out superfast fibre optic broadband across the country, which would boost business, reduce pressure on transport and future-proof British infrastructure.
:: £2 billion - to make cities outside London better for cycling and walking.
David Theiss, a researcher at the NEF, said: "HS2 is the largest transport investment in the UK's history. At the moment it amounts to a £33 billion gamble.
"Our research shows the Government is backing the wrong horse. Instead of pouring billions of pounds into a single line that will take 20 years to complete we should be spreading our bets on a wider range of transport investments that offer better value for money."
Transport Minister, Simon Burns, said: "Demand for long-distance rail travel has doubled to 125 million journeys a year in the past 15 years and by the mid 2020s the West Coast Main Line will be completely full.
"HS2 will provide the capacity needed in a way that will support thousands of jobs and billions of pounds worth of economic benefits."
He went on: "It is not a case of HS2 and nothing else. During 2014-19 we are investing over £9 billion on the current rail network, while latest figures show that over a one year period we spent upwards of £8.7 billion on our roads.
"We will continue to make significant investment into all modes of transport across the country."