Graham Robinson of Pinsent Masons, the law firm behind Out-Law.com, was commenting as Ed Balls, the Shadow Chancellor, said that a future Labour government would not support the proposed high speed rail link between London and the rest of the country if costs continued to rise.
Robinson described Balls' comments as "unwelcome news" at "a time when what the infrastructure needs is certainty around a pipeline of projects".
"That a project which could give much needed stimulus to the sector might be scrapped, even if the business case is sound, is worrying news for the UK's infrastructure in the future," he said.
"Despite all party agreement, and the findings of the recently-published Armitt Review commissioned by Ed Balls, the Labour Party is now casting doubt on one of the UK's most important infrastructure investments. Ed Balls should listen to the advice from his own review and hand decisions about Britain's long-term infrastructure needs to an Infrastructure Commission, as political wrangling is bad news for future infrastructure build in the UK," he said.
Published at the start of this month, the Labour-commissioned Armitt Review recommended that the Government hand over responsibility for identifying the UK's long-term infrastructure needs to an independent National Infrastructure Commission, which would then monitor its plans for meeting those needs. Doing so would encourage investment in long-term projects by reducing the influence of individual political parties in these processes, according to the report's author, former Olympic Delivery Authority (ODA) head Sir John Armitt.
HS2, the planned high speed railway between London, the Midlands and the north of England, has had the support of the leaders of England's three main political parties since its conception. However, Balls' comments about the increasing budget of the project follow similar criticisms by the Institute of Directors and Parliament's public spending watchdog, the Public Accounts Committee.
In his speech, Balls accused the Government of "mismanaging" the project. The Prime Minister and Chancellor had "put their own pride and vanity above best value for money for the taxpayer", he said; by making it clear that they would "go full stream ahead with this project - no matter how much the costs spiral up and up".
"Labour will not take this irresponsible approach," he said.
"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 £50bn for the future of our country," he said.
Robinson said that the UK needed "modern infrastructure to compete for trade in emerging markets", and to support the needs of a growing population. The work of the ODA during the London 2012 Olympics showed that the UK was capable of delivering major projects on time and within budget, he said.
"Confidence in Britain's ability to successfully deliver key infrastructure projects has improved significantly following London 2012 Olympics," he said. "Delivery of HS2 to meet a strict budget needs the same modern approaches to procurement as used by the ODA. The ODA proved that using a modern approach to procurement will mean that the construction sector can deliver a quality railway within agreed timescales and budget."
HS2 is due to be delivered in two phases, with the initial London to Birmingham phase of the line scheduled for completion in 2026. A proposed second phase of the project envisages the construction of an onward 'y network' connecting the line to Manchester and Leeds, as well as a spur to Heathrow Airport, by 2023. HS2 will cut journey times between England's two largest cities to 45 minutes, and support trains running at up to 250 miles per hour, according to the Department for Transport.