Later that decade he joined various eco-protests against road development across Britain and, with the Council of British Druid Orders, campaigned for open access to Stonehenge during the solstices.

[1] Pendragon is best known for his legal battles with English Heritage regarding the monument of Stonehenge in Wiltshire, a site of great religious significance to Neo-Druids.

[1][2] On 19 October 1998, with assistance from organisations such as Liberty who acted as his counsel, Pendragon had his case heard by the European Court of Human Rights in Strasbourg.

On 24 April 2009, he was ordered by Salisbury County Court to dismantle his camp and leave, following complaints from Wiltshire Council that he was obstructing traffic.

[6] He finally ended his protest on 19 May,[7] after English Heritage announced plans to move a section of the A303 underground, and to create a new visitor centre about a mile-and-a-half away from the stones.

[8] In August 2011, Pendragon filed a High Court appeal calling for the cremated remains of more than forty bodies to be immediately reburied.

[9][10] Pendragon has also voiced his opposition to English Heritage's plan to display three more sets of human remains at the new visitor centre, claiming that out of respect to the ancient British ancestors, replica bones should be on view instead.

[11] In 2020, English Heritage and the authorities controlling access to Stonehenge agreed along with members of the Druid and pagan communities that the Summer Solstice would not be physically observed as it used to be due to COVID-19 lockdowns.

In an interview with the BBC Arthur Pendragon stated his understanding for this decision, noting that the Spring Equinox ceremony had also been cancelled.