April 2015 saw the British Championships, which doubles as the selection meet for the summer Internationals, return to London for the first time since the 2012 London Olympics. The 2015 Trials produced some excellent results in the pool, heralding signs of a major return to form for Britain's senior swimmers.
"It was a real honour to be part of such a fantastic team heading out to Kazan in August 2015 for the World Championships. I was really happy to go on to take 5th place in the final of my main event, the 1500m freestyle, on the last day in Kazan. The experience I gained with the team, who went on to produce British Swimming's best-ever performance at a World Championships, was a very important stepping stone for me as the Rio 2016 Olympic Games drew ever closer."
Summer 2015 brought GB's most successful ever World Championships, with the team finishing 4th in the swimming events after claiming 9 medals in the pool. In his Worlds debut, Stephen slashed over 4 seconds off his Scottish record in the 800m freestyle on Day 3, finishing 7th in the final, before going on to a 5th place finish in the 1500m freestyle final on the closing day of competition.