Has HS2 finally hit the buffers? Ed Balls refuses to write a 'blank cheque' and argues £50bn could be better spent elsewhere Labour backed HS2 between London and the north in 2010 manifesto But costs have soared amid doubts about economic benefits Shadow chancellor put new emphasis on 'value for money' The ambitious High Speed rail link between London and the north was dramatically derailed today, as Ed Balls declared there could be better ways to spend £50billion. The shadow chancellor appeared to withdraw Labour's full-throated support for the project which it backed at the 2010 election. Mr Balls said there would be "no blank cheque" for the scheme as he signalled that other big money projects should jump the queue for funding. Buffers: Labour's shadow chancellor Ed Balls signalled that he thought the £50billion earmarked for HS" could be better spent elsehwere The Labour party manifesto in 2010 insisted a new high speed rail line linking north and south was 'at the heart of our growth plan'. It promised journey times will be 'slashed' and more capacity would be freed up for freight and commuter services. But the project ran into trouble when the government admitted earlier this year that the bill had soared by £10billion to £42.6billion. Mr Balls used his keynote address at the Labour party conference in Brighton to question the entire basis for HS2. With construction likely to last several parliaments, cross-party support has been vital to ensure it went ahead. Mr Balls backed more long-term investment in infrastructure but added: "We must also set the right priorities and get value for money." He went on: "We support investment in better transport links for the future. And we continue to back the idea of a new North-South rail link. But under this government the High Speed 2 project has been totally mismanaged and the costs have shot up to £50 billion. David Cameron and George Osborne have made clear they will go full steam ahead with this project - no matter how much the costs spiral up and up. They seem willing to put their own pride and vanity above best value for money for the taxpayer. Duo: Mr Balls and deputy Rachel Reeves during a visit to a nursery in Brighton Labour will not take this irresponsible approach. So let me be clear, in tough times - when there is less money around and a big deficit to get down - there will be no blank cheque from me as a Labour Chancellor for this project or for any project. Because the question is - not just whether a new High Speed line is a good idea or a bad idea, but whether it is the best way to spend £50 billion for the future of our country. HS2 will run from London Euston to Birmingham from 2026, and then form two routes to Manchester and Leeds by 2032. It is intended to allow trains to run 250 miles per hour and cut journey times significantly. Opponents say it will cause environmental damage, loss of homes and disruption to communities which will claim millions in compensation. Katja Hall, CBI Chief Policy Director, said:'We've always said that the government must redouble its efforts to sell the benefits of HS2 while keeping a tight lid on costs. 'But let's not forget why this project matters. HS2 will connect eight of our ten biggest cities, boost regeneration projects across the country for years to come, and will avert a looming capacity crunch on the West Coast mainline. Ex-Business Secretary Lord Mandelson was among the most senior Labour figures to speak out against it, arguing that those who previously backed the plan "should not offer it an open cheque and should, instead, insist on keeping their options open." Labour's plans were based on an estimated cost of £30billion and the central assumption that construction would spread growth across the country. This was "neither quantified nor proved," said the peer. I once supported High Speed 2. There are no simple options when it comes to transport - but I now fear HS2 could be an expensive mistake," he said. However, both the coalition and Labour frontbenchers have remained committed to the project - until now.