The cost of the long-awaited A66 dualling scheme between North Yorkshire and Cumbria could rise to £2.67 billion – more than double its original estimated price.

The potential figure was disclosed by National Highways at the Highways UK conference, raising further questions over the cost of one of northern England’s biggest road infrastructure projects.

The development comes amid renewed uncertainty over the scheme’s delivery, just days after the Government confirmed that construction would be spread across a revised nine-year programme, with work due to begin in November 2026.

National Highways stressed that no final decisions had been made on the programme or its funding.

“We will set out our full programme through our Strategic Business Plan and Delivery Plan in due course, which will reflect the outcome of the Government’s consultation on changes to RIS3. No final decisions have yet been made,” a spokesperson said.

The Government’s Autumn Budget documents confirmed that main construction works on the A66 would begin in November 2026, delivering a continuous 50-mile dual carriageway between the M6 and A1(M).

However, the revised timetable represents a significant extension to the previously anticipated five-year delivery period, with the project now expected to take nine years to complete.

The announcement has already attracted criticism from Richmond and Northallerton MP Rishi Sunak, who described the delays as “frustrating”.

The A66 Northern Trans-Pennine project will upgrade the remaining single-carriageway sections between Scotch Corner in North Yorkshire and Penrith in Cumbria, improving connectivity between the North-East and the North-West.

The potential increase in cost, alongside the extended delivery timetable, adds to the challenges facing a scheme that has experienced years of delays and uncertainty.

(Picture: National Highways)