A backyard-format endurance event held on the Isle of Portland, Dorset. Runners complete a standard 4.167 mile (6.7 km) loop on the hour, every hour, continuing until only one participant completes a final solo lap. The course terrain and surface are determined by the specific venue layout but typically involve trail, track or mixed ground. Race operation follows established backyard ultra rules, with site-specific logistics, facilities and any support arrangements set out by the organiser.