A campaign group is planning a legal challenge over the transport secretary’s decision to approve a £1.7bn tunnel near Stonehenge.
The Stonehenge Alliance group has instructed a legal team to investigate the lawfulness of the decision.
The group said the plan to dig a two-mile (3.2km) tunnel alongside the A303 near the Unesco world heritage site was “wasteful and destructive”.
The BBC has approached the Department for Transport (DfT) for a comment.
Transport Secretary Grant Shapps approved the project earlier this month against the recommendations of planning officials.
The Planning Inspectorate had recommended Mr Shapps withhold consent, but the DfT said that the benefits of the scheme outweighed the potential harm.
Unesco previously said the scheme would have an “adverse impact” on the surrounding landscape.
Campaigners are worried that the work will have a detrimental impact on the wider Stonehenge world heritage site – which the tunnel would go through.
Tom Holland, from the Stonehenge Alliance, said he was “stunned” that the government had decided to approve the plans.
He said: “I fully back the move to test whether Grants Shapps acted legally in approving this highly wasteful and destructive road scheme.
“The government has ignored advice from both Unesco and the independent panel who presided over a six-month examination.”
Mr Holland added: “I urge everyone who cares about the Stonehenge world heritage site to support this legal action.
“There is still a chance to stop the bulldozers moving in and vandalising our most precious and iconic prehistoric landscape.”
Highways England and English Heritage support the scheme, which is expected to begin in 2023 and take five years to complete.