The Bump device, which makes an audible alert when the wearer is too close to others, will be worn by the 100 elite competitors and 500 event coordinators.

The race, 19 laps of a closed course in St James's Park, screened from public view, is the first major marathon since the Covid-19 pandemic, organisers say.

Non-elite runners can participate in a 24-hour virtual version of the event.......