A London-based 100 km ultra built around repeating 25 km route options (North, South, East and West) with a central event base, so it feels like a structured “London tour” rather than a single point-to-point trail. The organiser’s format uses an indoor HQ and checkpoint set-up per section, with the full rules, cut-offs and day logistics defined in the official event information.

• Other races at the same event:
25K and 50K options (same weekend).