Great Britain won their 23rd gold medal with Charlotte Dujardin claiming her second dressage title of London 2012.

The 26-year-old's victory on Valegro and bronze for team-mate Laura Bechtolsheimer are Britain's first individual dressage medals.

It comes after the pair helped seal a record 20th GB gold in the team event and takes GB's medal total to 50.

Boxer Nicola Adams will add to the haul as she is already guaranteed silver but could turn that into gold at 16:30 BST.

Britain's third sailing medal of the Games is assured as Luke Patience and Stuart Bithell are guaranteed silver in sailing's 470 class.

The pair are due to go for gold against the Australian crew of Mathew Belcher and Malcolm Page, but their final race has been delayed due to a lack of wind at Weymouth.

In taekwondo , 19-year-old Jade Jones is a medal prospect as the fourth seed, while the men's hockey team can assure silver by beating Netherlands at 20:30.

Flyweight Adams has already created history by guaranteeing Britain's first women's Olympic boxing medal but she could become the sport's first Olympic champion when she faces three-time world champion Ren Cancan of China.

Dujardin's gold increases Britain's best gold medal total for 104 years. Only in the London Games of 1908, where the hosts won 56 medals, have Britain done better.

With the team of Dujardin, Bechtolsheimer and Carl Hester having already tasted victory at Greenwich Park, the further gold and bronze medals complete an unprecedented haul for the GB dressage team.

Team GB are three medals ahead of the 2008 Beijing total four years' ago, and two above their minimum London target of 48.

Earlier, swimmer Keri-Anne Payne finished fourth in the women's open water race in Hyde Park.

Elsewhere, Jamaica's Usain Bolt is aiming to become the first man to successfully defend the Olympic 100m and 200m title.

Having won the 100m already, he will hope to keep competitors including compatriot Yohan Blake at bay from 20:55.

Kenya's David Rudisha might not have the same profile as Bolt but in the 800m the world record holder could produce something almost as special in the final at 20:00.