Image source, Supplied Image caption, Mark Peart won a Guinness World record for completing the race in full fire-fighting kit ByGina Bolton and Tom Ingall, Yorkshire Published Just now A firefighter has smashed the world record for the running fastest London Marathon in full kit. Mark Peart, 38, from South Yorkshire Fire and Rescue, completed the 26.2m (42km) course in three hours, two minutes and 57 seconds on Sunday. The previous record stood at three hours and 41 minutes.