The British government on Friday approved the construction of a controversial road tunnel near the historic Stonehenge site in southwestern England. 

The decision comes two years after campaigners won a legal battle to throw out permission for the project that would include digging a new two-mile tunnel running past the UNESCO World Heritage Site.

The £1.7 billion project is intended to ease congestion on an existing main road to southwest England that gets especially busy during the peak holiday periods. 

It was initially authorised in 2020 by Grant Shapps, the transport minister at the time, despite a panel of planning experts warning of "permanent, irreversible harm" to the area.

The following year the decision was successfully challenged in the High Court.

But the court stressed that its ruling was not on the merits of the scheme but on the legality of the minister's granting of approval.

In a 64-page letter granting fresh approval, Shapps' successor Mark Harper said he was "satisfied" that the project's "harm on spatial, visual relations and settings is less than substantial and should be weighed against the public benefits".

Opponents of the plan have warned against the massive engineering project in an area full of archaeological treasures around the standing stones, while UNESCO said the site could lose its World Heritage Site status if construction goes ahead.

Steve Gooding, head of the RAC motoring group, indicated that opponents of the project will likely mount another legal challenge.

"This saga is starting to feel almost as old as the stones themselves and it's not over yet," Gooding said.