Ellie Simmonds won her second 2012 Paralympics gold with a world record in the SM6 200m individual medley.
The 17-year-old Briton, who defended her 400m freestyle title on Saturday, broke her own record, set in the heats, to win in three minutes 5.39 seconds.
Team-mate and 2004 Athens gold medallist Natalie Waddon was third behind Germany's Verena Schott.
GB's Sascha Kindred, the six-time Paralympic champion, took silver behind China's Xu Qing in the men's event.
"It's amazing in front of this home crowd," Simmonds told BBC Sport.
"I'm so pleased and I don't know what my coach has done to get me in this shape."
Anastasia Diodorova held a 10m advantage heading into the final length, but freestyle-specialist Simmonds powered past the Russian.
"I did worry about her, but my front crawl is my best event and I just had to do all I could," said Simmonds, who received her medal from Prime Minister David Cameron.
"I have two races to focus on now, the 50m and 100m [which Simmonds won in Beijing] and hopefully I'll feel good when I wake up tomorrow."
Waddon missed out on silver by only a hundredth of a second.
"I can't believe it was so close and I'm annoyed, but I'm happy to get a medal," she told BBC Radio 5 live.
Kindred, 34, who finished a disappointing fourth in the SB7 100m breaststroke final on Saturday, found China's Xu too tough a rival in the final.
"This is the biggest stage in the world and you have to swim personal bests to stay on top and I did with a European record [2:41.50], but Xu swam really well and I have to give him that," said Kindred.
Great Britain's Susie Rodgers won bronze in the women's 100m freestyleS7, while team-mate Jonathan Fox, the 100m backstroke Paralympic gold medallist, finished fifth in the men's S7 100m freestyle.
Great Britain's women's 4x100m freestyle relay team rounded off the action on day five of the Games with a bronze medal.
Stephanie Millward, Claire Cashmore, Susie Rodgers and Louise Watkin were narrowly beaten to silver by just 0.14 secs by the USA, with the Australians winning in a new world record time of 4:20.39.