Jasmine Harrison on her record breaking swim. See SWNS story SWLNswim. A 23-year-old endurance athlete has made history after become the first woman to swim the entire length of Britain. Jasmine Harrison completed her grueling 900-mile (1448 km) challenge in 110 days when she swam into John OGroats harbour on today (Oct 18) at around 4.30pm.And this time makes her the second fastest person ever to complete the crossing, behind Ross Edgley, who took 62 days, but in front of Sean Conway, who took 135 days. The swimming instructor, who became the youngest woman to row solo across the Atlantic last year, battled 20ft waves and treacherous fork lightening during the journey.