In 1997, he was the site manager of a dig of an 8th century battlefield near Carbury in rural England. Warmsly firmly believed the battle in question was the Battle of Camlann, the final, apocalyptic conflict between King Arthur and his arch-foe, Mordred. It was a view characterised by his peers as "an obsession" with Arthuriana.
Warmsly was a tireless and meticulous archaeologist. He spent ten years excavating the battlefield, mostly by himself, with little to show for it except a splendid 8th century scabbard. He kept this on display on the wall of a hotel run by his friends Pat and Elizabeth Rowlinson.
Highly educated and passionate about his work, Warmsly enjoyed sharing his knowledge with anyone interested. He also enjoyed quoting Arthurian poetry, particularly Thomas Malory's Le Morte d'Arthur. Peter was angry with UNIT for trying to evacuate him until the Doctor hypnotised him. After this, he complied. (TV: Battlefield)