Topoguide de randonnées (en anglais) - London LOOP - London outer orbital path | TrailblazerAll in one guide to walking the complete London LOOP London Outer Orbital Path, including trail maps, places to stay, where to eat and what to see, public transport information. The London LOOP London Outer Orbital Path is a 150 mile circuit of the country s capital, starting at Erith and finishing at Purfleet on Thames. It stays within the M25 and sticks by and large to the Metropolitan Green Belt that buffer zone of green largely undeveloped land