Sir Chris Hoy's historic sixth gold medal has helped Britain to its best Olympic performance for more than a century.
The track cyclist's win at the Velodrome means he has more golds than any other British Olympian. Sir Steve Redgrave has five.
Team GB's medal tally is 48 - 22 gold, 13 silver and 13 bronze - making it the most successful Games since the London Olympics of 1908.
Sir Chris, 36, said: "It's the most incredible feeling when you finally cross the line and you realise you've won. This is the perfect end to my Olympic career. I look back four Games ago to Sydney and I was just over the moon to have a silver medal. If I'd stopped then I'd have been a happy boy, but to have gone to Athens, Beijing and to here, I can't put into words what it means."
His victory in the men's keirin came shortly after the new star of women's cycling, Laura Trott, 20, won her second gold of the Games in the women's omnium. An ecstatic Trott joined an elite club of British women to have won double gold at a single Games, including Dame Kelly Holmes and Rebecca Adlington. She said: "I can't believe this is happening to me, I really can't. I am so happy."
The double Olympic champion only took up cycling because of poor health after being born with a collapsed lung and diagnosed with asthma. Referring to her team-mates, some of whom were her childhood heroes, she added: "I never actually believed I would be in the same team as them."
One of Trott's heroes, Victoria Pendleton, could only manage a silver in her sprint showdown with Australian arch-rival Anna Meares. The 31-year-old said: "I've been a bit overwhelmed with emotion. I would have loved to have won on my final race but I'm just so glad that's it all done and I can move on."
Elsewhere, Alistair Brownlee was victorious in the triathlon, ahead of his brother Jonny, who won bronze, while the dressage team also secured gold.
There was an unexpected bronze for Londoner Robbie Grabarz in the high jump, and a silver for Nick Dempsey, competing in men's windsurfing in Weymouth.
The medal haul will rise further with guaranteed medals for Team GB in the boxing, and podium potential today for Nick Skelton in the individual jumping equestrian event.