Tokyo is a swim too far for Britain's Burnell

FILE PHOTO: Swimming - 18th FINA World Swimming Championships - Men's 10km Open Water Final - Yeosu EXPO Ocean Park, Yeosu, South Korea - July 16, 2019. Jack Burnell of Britain competes. REUTERS/Evgenia Novozhenina/File Photo

LONDON (Reuters) - British marathon swimmer Jack Burnell, who was controversially disqualified at the end of the 10km open-water race at the 2016 Rio Olympics, announced his retirement on Tuesday only months before the Tokyo Games.

Burnell, 27, had been set to swim in a qualifier for the delayed 2020 Olympics scheduled for Fukuoka in May but that event is now under review by world body FINA.