Swimming-Relay record falls for third time in a day

(Updates with record falling again) KAZAN, Russia, Aug 5 (Reuters) - Britain set a world record in the mixed 4x100 metres medley relay at the world swimming championships on Wednesday as the mark fell for the third time in a day. In the final, Chris Walker-Hebborn, Adam Peaty, Siobhan O'Connor and Fran Halsall clocked a combined time of three minutes 41.71 seconds to break the record of 3:42.33 set by the United States in the heats earlier on Wednesday. American quartet Ryan Murphy, Kevin Cordes, Kendyl Stewart and Lia Neal had themselves wiped more than three-and-a-half seconds off the short-lived world record of 3:45.87 which Russia set in winning the second heat. The mixed medley relay is being held at the world championships for the first time but is not on the Olympic programme. (Reporting by Rod Gilmour, Editing by Clare Fallon)