Stop HS2 campaign poster
Stop HS2 campaign poster (Reuters)

Britain's much-anticipated £50bn high-speed rail line (HS2) linking London and the north at speeds up to 250mph was supposed to be the jewel in the crown of the UK's struggling rail network, dragging it into the 21st century and bringing a huge boost to the national economy. Yet it may never be built.

As politics has, inevitably, taken the project over, so its fortunes have taken a major turn for the worse amid growing signs the Labour party may yet pull the plug on the entire scheme believing the public are sceptical.

Prime Minister David Cameron may be the chief cheerleader for it, but this massive 15-year undertaking has become the Opposition's project to kill or create as they see fit. And it is looking like it might be kill.

Any project of this size requiring public investment is always either going to start off political or quickly turn political and the only real surprise is that it seems to have taken HS2 a long time to get there. Well it is a rail network.

But what we are now seeing is real doubt being raised over its future as Labour and the Tories consider the relative merits of being seen as either the party that placed the jewel in that crown, or the one which stopped a £50bn folly, a vanity project.

The prime minister has rightly accepted that, with a project as long-term as rebuilding the nation's rail network, it would simply not be realistic to expect it to even start without full, robust cross-party agreement.

"If Labour continues to support it, which they should and I believe they will, then of course it will have all-party support and it will proceed," he said at the weekend.

"If Labour are to run away from this they will be letting down the Midlands, they will be letting down the North, they will be kicking sand in the face of council leaders right across the country who want this to go ahead," he added.

But at the moment, Labour is refusing to give a "blank cheque" to the scheme and is clearly enjoying watching Cameron wriggle.

Shadow Chancellor Ed Balls first signalled the change of tack when he told Labour's annual conference: "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."

Speculation that Labour is having second thoughts has only intensified since and Deputy Leader Harriet Harman told the BBC's Marr Show: "We are in favour of rail infrastructure for commuters and also for long-distance travellers and freight, but not at any cost, and what Ed Balls is saying is we have to keep a strong eye on the costs as well as on the benefits.

"It's no good the government simply complaining about people who are raising these issues. They should be addressing these issues, controlling costs and being properly analytical about the benefits," she said.

Treasury Secretary Danny Alexander, meanwhile, said he was absolutely confident the project would be completed within budget and that he had a good grip on the costs.

Earlier this month it was revealed that a report by KPMG, which boosted the government's case that the link would boost the nation's economy by £15bn a year, had also found 50 areas, including Bristol, Cambridge and Aberdeen , could lose up to £220m each.

Meanwhile there is a powerful anti-HS2 campaign amongst residents on the proposed line of the project and worries that it has become a huge vanity scheme, reminiscent of the Millennium Dome which turned into a PR nightmare for the last Labour government.

Ministers seem to accept they have so far failed to make a strong, positive case for the link, but that is about to change with a new campaign planned to push the benefits of the project.

That was helped by a report from Network Rail suggesting there would be 14 years of disruption and weekend rail closures if the scheme did not go ahead. And a new government report setting out the necessity of the project is due this week.

So what travellers, residents and businesses are now facing is potentially months of political wrangling and uncertainty as the pro and anti lobbies make their cases.

It may all seem a little late in the day, but the battle over HS2 is really only just beginning.