World championship silver medallist Hannah Miley led five Britons into the Olympic Games on Saturday on the first day of the national championships at the Games\' Aquatics Centre. Miley led from start to finish to win the 400m medley in a time of four minutes 32.67 seconds. Aimee Willmott also booked her place in the squad in the same event, while Roberto Pavoni and Joe Roebuck secured their places in the men\'s 400m medley. Robbie Renwick also made sure of his place at the Olympics with victory in the men\'s 400m freestyle. \"I wasn\'t really expecting that time. I am really chuffed (pleased) with how it went, it felt great,\" said Miley. \"The crowd and the atmosphere was electric so it is going to be really exciting at the Olympic Games. It\'s taken a huge pressure off me knowing I\'ve made it. I\'ve done what I needed to do.\" Willmott lowered her personal best by more than a second to 4min 37.48sec after failing to make the world championships in China last year. Pavoni saw off Roebuck in the men\'s 400m medley, recording a personal best of 4:12.43, 2.05sec ahead of his compatriot. \"I\'m 20 years old, it\'s my first Olympics, I\'ve been dreaming about this ever since we found out in 2005 it was going to be here,\" said Pavoni. \"I live just 20 minutes down the road -- I might even stay at home for the Games.\" Renwick also booked his spot on the team in the 400m freestyle with a time of 3:46.73. Later in the week, double Olympic champion Rebecca Adlington and 50m backstroke world champion Liam Tancock will also be hoping to make sure of their places on the team.