The RHA has said it remained optimistic that a £1.5bn upgrade of the A66 would go ahead, after a campaign group launched a legal challenge against the project.

The A66 Northern TransPennine road scheme involves dualling 18 miles of road between Penrith and Scotch Corner. National Highways said the upgrade would provide safer journeys along a route that currently sees high numbers of accidents.

But the Transport Action Network (TAN) said the secretary of state’s decision to grant a development consent order was flawed and it would make the route more dangerous.

“The £1.5bn A66 Northern Trans-Pennine represents very poor value for money and will cause great harm to important landscapes and wildlife,” said Chris Todd, TAN founder and director. “At a time when we are experiencing more flooding due to climate change, it will drive up carbon emissions by 2.7m tonnes. By encouraging more HGVs it will also make the existing parts of the A66 that are already dualled more dangerous.

“We believe the secretary of state has not considered these issues properly, gambling away £1.5bn of taxpayers’ money in the process.

“National Highways should instead be implementing cheaper and quicker safety measures on this road, for a fraction of the cost and without harming the environment or taking us backwards on climate,” he added.

However, James Barwise, the RHA’s policy lead for infrastructure, said freight transport contributed billions to the UK economy and the scheme must proceed.

“Households, businesses, and the public sector rely heavily on companies across our industry, and we want to keep business and the UK supply-chain moving and performing at the highest possible levels,” he said. “We previously welcomed investment in the scheme as the A66 is the key strategic road link between the M6 and the A1 for businesses in Cumbria and North Yorkshire.

“We remain optimistic that this vital piece of infrastructure will proceed as planned. HGVs account for a quarter of all traffic on this stretch of the A66 and delays to journeys can have a negative effect on businesses, including lost working time and missed shipment slots.”

Barwise added that the RHA would continue to liaise with National Highways and the Planning Inspectorate and that road network investment was the key to alleviating congestion and ensuring journeys were made safely and efficiently.