In the pool, the host nation's gold-medal hopes begin (and probably end) with Becca Adlington. In Beijing, Adlington won double gold – unexpectedly in the 400-meter freestyle and blitzing a world record in the 800. She was the first British swimmer to win more than one gold medal at an Olympic Games since 1908. After a post-Beijing dip because of a bout with nerves, she returned to form to win gold and silver in the 800 and 400 in the 2011 world championships.

David Moir/REUTERS
Rebecca Adlington laughs during a training session in Edinburgh, Scotland, Saturday for the London 2012 Olympics.