British trio through to semi-finals

World Championship finalists Ellen Gandy and Jemma Lowe and British record holder Fran Halsall all negotiated the heats of the 100 metres butterfly on the first morning of the Olympic trials at the Aquatics Centre. With only two slots available on the Great Britain team, one world-class swimmer is set to miss out. As a test event overseas swimmers are allowed to compete and world record holder Saraj Sjoestroem was quickest on Saturday morning in 58.28 seconds, with Gandy heading the Britons into tonight's semi-finals in 58.71secs. Gandy, world silver medallist in the 200m butterfly, said: 'That was a bit faster than I planned to go. 'It was a case of blowing the cobwebs away and getting my first race under my belt.' The Melbourne-based swimmer described the pool and Olympic Park as 'amazing'. Halsall had missed out in this event at last year's World Championships when Lowe pipped her to the second berth by one hundredth of a second. Both Gandy and Lowe reached the final in Shanghai, finishing fifth and eighth respectively. Halsall was the second-fastest Briton in 59.01 and said: 'I just wanted to go out in the first 50 and then ease down. I just wanted to qualify.' Lowe was 12th through in 59.89 and said: 'I just felt really relaxed. 'I'm really happy to go into the meet and race fast.' Joe Roebuck was the fastest Briton through to tonight's final of the 400m individual medley in 4:17.78, two hundredths of a second ahead of world finalist Rob Pavoni. Markus Rogan of Austria headed the heats but overseas swimmers will compete in finals separate to the British athletes. Robbie Renwick is the fastest into tonight's 400m freestyle final (3:50.70) ahead of Ieuan Lloyd who edged out world record holder Paul Biedermann in his heat.