Civil engineers have reacted with alarm warning the move would be short-sighted and undermine the UK net zero goals for 2050.

Prime minister Rishi Sunak and Chancellor Jeremy Hunt are in talks about scrapping the project’s second stage in a bid to save £35bn for tax cuts ahead of the next general election, according to a report in the Independent based on a photograph of a leaked document.

Rumours were further stoked when Downing Street refused to guarantee that HS2 will run to Manchester as planned.

Civil Engineering Contractors Association chief executive Alasdair Reisner said: “In recent years, the Government has taken successive chunks out of its proposed plans for HS2.

“We are now at the point where very little of the northern elements that were originally put forward are now looking set to go ahead.”

He added: “Cancellation of such a nationally-significant project will level down rather than level up, massively undermining the ability of the UK economy as a whole to grow, and threaten delivery of Net Zero by 2050.

“In simple terms, a decision to axe the northern sections of HS2 would mean that we are unlikely to see high speed rail in the North anytime in the first half of this century.

“No British Government has made such a short-sighted and self-harming decision since Harold Wilson’s administration stopped work on the Channel Tunnel in the mid-1970s.

“Cancelling the second leg of HS2 would not only make the UK an international laughing stock: it will actively undermine the life-chances of generations of Britons, harm our ability to fight climate change, and destroy trust in politics to deliver on a better future for us all.”

Henri Murison, chief executive of the Northern Powerhouse Partnership, also warned of the wider impact.

“Any decision to curtail this project any further would do serious damage to the government’s relationship with the business community, both Northern-based businesses and inward investors, who have made long-term investment decisions based on previous promises,” Murison said.

“Cancelling Phase 2b would also make it impossible to improve East-West connectivity across the North as promised in the Integrated Rail plan.

“It would remove the most critical remaining section of Northern Powerhouse Rail between Manchester Piccadilly and Manchester Airport which is vital for getting passengers from Liverpool across the Pennines,” he continued.