The High Court has quashed a development consent order made by the Secretary of State for Transport which gave the green light to the construction of a £1.7bn tunnel at the Stonehenge World Heritage Site.
In Save Stonehenge World Heritage Site Ltd, R (On the Application Of) v Secretary Of State For Transport  EWHC 2161 (Admin) the claimant sought to quash the Secretary of State's decision to grant Highways England's application for a development consent order (DCO) for the project.
A number of grounds of challenge were advanced, including a claim that the Secretary of State failed to assess the impact on individual heritage assets in the World Heritage Site.
Accepting this ground, Mr Justice Holgate found that the Secretary of State did not take into account two specific appraisals from an Environment Statement and a Heritage Impact Assessment of additional assets on the land, and therefore did not form any conclusion upon the impacts upon their significance, whether in agreement or disagreement.
Holgate J said this involved a material error in law.
He added: "We have no evidence as to what officials thought about those assessments.
"More pertinently, the decision letter drafted by officials [...] was completely silent about those assessments. The draft decision letter did not say that they had been considered and were accepted, or otherwise."
As such, Holgate J said, the Secretary of State was not given legally sufficient material to be able, lawfully, to carry out the "heritage" balancing exercise required by the National Policy Statement for National Networks and the overall balancing exercise required by the Planning Act 2008.
The second ground that the campaigners were successful on was the claim that the Secretary of State failed to consider mandatory material considerations, specifically the existence of at least one alternative.
Detractors of the plan offered alternative options to the tunnel's design which included lengthening the tunnel so that the western portals, which were set to be placed within the designated World Heritage Site, would be placed outside the WHS.
Holgate J said the relative merits of the alternative tunnel options, proposed by objectors to the approved plan, were "an obviously material consideration" which the Secretary of State "was required to assess".
He added: "It was irrational not to do so. This was not merely a relevant consideration which the SST (Secretary of State) could choose whether or not to take into account."