Arthur Uther Pendragon (born John Timothy Rothwell, 5 April 1954) is a British eco-campaigner, Neo-Druid leader, media personality, and self-declared reincarnation of King Arthur, a name by which he is also known. Pendragon was the "battle chieftain" of the Council of British Druid Orders.

Born to a working-class family in Wakefield, Yorkshire Pendragon served in the British Army's Royal Hampshire Regiment before being discharged following an injury. Identifying as a greaser, he formed a biker club known as the Gravediggers, moving in counter-cultural circles at free festivals around Britain.

After reading a book on King Arthur by the occultist Gareth Knight, he leapt to the conclusion that he was the reincarnation of the mythical king and changed his name by deed poll. He formed the Loyal Arthurian Warband out of his supporters and began describing himself as a Druid. Angered that English Heritage charged entry to visit Stonehenge, using the money for restoration and preservation of the archaeological site in Wiltshire, between 1990 and 1991 he picketed outside the site on a daily basis.

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. For several years, Pendragon engaged in direct action protests and was repeatedly arrested. English Heritage agreed to implement open access at the solstice in 2000. Pendragon later focused on campaigning for the return of human remains removed from Stonehenge by archaeologists in 2008. He continued to call for free access to the site.

In 1986 he bought a sword called Excalibur in a Farnborough shop; its seller stated that it had been the prop in the 1981 film Excalibur.

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. Throughout the 1990s, he campaigned for the removal of the four-mile exclusion zone which was established each year during the summer solstice. 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. He claimed that the exclusion zone around Stonehenge was restricting his freedom of thought, conscience, religion and freedom of expression, in contravention of Articles 9, 10 and 11 of the European Convention of Human Rights. The court decided in favour of the UK government. However, the exclusion zone was lifted the following year, after an unrelated case brought before the House of Lords ruled that the public have a right to assembly on a public highway.

In June 2008, Pendragon set up a protest camp on a byway near the monument, demanding free access to Stonehenge for everyone. He insisted that the fences surrounding the site should be removed, and that the two nearby A roads (the A344 and A303) should be closed or redirected. He occupied the byway for ten months, and obtained 8,000 signatures in support of his petition. 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. Pendragon defied the order. He finally ended his protest on 19 May, 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.

In August 2011, Pendragon filed a High Court appeal calling for the cremated remains of more than 40 bodies to be immediately reburied. The remains had been exhumed from a burial site at Stonehenge in 2008, to be studied at Sheffield University. The appeal was rejected. 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.