In a move that could derail Europe’s largest public infrastructure project, British Prime Minister Theresa May, battered and bruised by Brexit, is expected to leave office later this year. The multibillion dollar plan to build HS2 — a high-speed rail line linking London with the North of England — could be cancelled.

Opponents of the plan have been protesting against it for almost a decade. Now, they say, victory might finally be in sight.

“Oddly enough, when they’re just about to start building it, we have more chance of stopping it than we ever had,” said Joe Rukin of the “Stop HS2” campaign group, who was taking part in a protest at one of the project’s construction sites just north of London.

Rukin believes that Theresa May’s eventual resignation could spell the end of the line for HS2, as Conservative politicians vie with each other for the leadership of the party.   

“It seems to be a pre-requisite for anyone that wants to succeed her as the next leader of the Conservative Party that they will cancel HS2, such is the grassroots opposition to the plan. “ he said.

The project has met its fiercest opposition from the mostly Conservative-controlled electoral districts that lie in the picturesque and tranquil southern countryside that the proposed line will cut through. Residents say they are anxious about noise. But Rukin maintains that an even bigger concern is the escalating projected cost of the project.

Originally put at roughly $45 billion, the official estimate for the line has spiraled to approximately $75 billion, while independent forecasts suggest that $135 billion (£100 billion, in local currency) is a more realistic figure. Rukin claims that if you add the costs of integrating the new line with the rest of the U.K. rail and road network, it will cost far more.

“At a time of austerity, you can understand why politicians are thinking: ‘Getting rid of this might be a vote winner,'” he said.

Not so, it seems, in the north of England, where the project is much more popular. Supporters say the line will provide much-needed capacity on the rail network, knit the country closer together and boost the underperforming parts of the northern economy. 

“Why shouldn’t northern businesses and northern business people have access to this world-class infrastructure?” asked Henri Murison, director of the Northern Powerhouse Partnership, an organization that regards itself as a voice for businesses and civic leaders in the region.

Murison believes that candidates for the Conservative party leadership would be ill-advised to curry favor with their grassroots supporters in the south by promising to scrap HS2; he said they risk alienating potential voters in the north.  

“Although it has a significant strength in the south of England, the Conservative party has demonstrated over previous years, electorally, that unless it can succeed in the north of England, it’s unlikely to form a majority government,” he said.  

Murison claims that the costs of the project are now under control. He points out that $5 billion has already been spent preparing for the construction of the line, and believes that — regardless of a change in the Conservative Party leadership — HS2 is now unstoppable.