Swimming - Britain fastest through to relay final, Phelps' last race

By Mark Trevelyan RIO DE JANEIRO (Reuters) - Britain qualified fastest on Friday in the men's 4x100 metres medley relay, threatening to spoil the party for Michael Phelps when he swims the last race of his epic Olympic career on Saturday. The British team of Chris Walker-Hebborn, Adam Peaty, James Guy and Duncan Scott won the first heat in 3 minutes 30.47 seconds, with Peaty making his first appearance since winning gold in the 100m breaststroke on Sunday. The U.S. men won the second heat in 3:3