Dominant victories by the men's four and the lightweight women's double sculls sparked more scenes of jubilation at Dorney Lake and took the host country's tally of golds to four, one more then New Zealand.
With the British also claiming a silver in a controversial final of the lightweight men's double sculls, they finished with nine medals — four golds, two silvers and three bronzes — to surpass the country's record total of eight from the 1908 Olympics. Those games were also held in London.
"It's the best ever Olympics for rowing," Britain coach Juergen Groebler said. "I think we should be honest with ourselves — it is a big, big result."
To put the achievement into context, if the British rowing squad was to be placed on the overall medals table at the London Games straight after the last final of the regatta, it would sit in 11th place.
In the two other finals raced under gloomy skies, Miroslava Knapkova of the Czech Republic sealed a wire-to-wire victory in the women's single sculls to add an Olympic title to her world crown from 2011, and Denmark won its only gold of the regatta through Mads Rasmussen and Rasmus Quist in the lightweight double.
That race had to be restarted after the seat of British rower Zac Purchase came loose, forcing him and Mark Hunter to stop rowing. Despite a complaint from the French, the race was able to start again because it hadn't progressed more than 100 metres.
"It was good for us as we'd had a bit of a bad start," Quist said. "Because we needed to start over, it gave us the time to have a quick chat."
The Danes' late surge saw them overtake defending champion Britain in the last 100 metres.
"There is no feeling for it — maybe the same as the first time you hold a new baby in your arms," Rasmussen said.
Australia, one of rowing's traditional powers, ended a disappointing regatta in ninth place — behind the likes of Ukraine and South Africa — and without any gold medals.
One of their biggest hopes was the men's four but in the most eagerly anticipated of Saturday's four finals, they were outpowered and outmanoeuvred by Britain, which retained its title for the third straight games.
Adopting the tactics usually employed by the Australians, the British crew of Alex Gregory, Pete Reed, Tom James and Andrew Triggs Hodge went out hard from the start and wasn't passed. Australia was never more than a boat length behind but couldn't respond in the final stretch passed the packed grandstands.
"We are glad to have been part of one of the best fours races there has ever been," said Drew Ginn, who was looking to win gold at a fourth Olympic Games — a feat never achieved by an Australian. "We always wanted a drag race, something for everyone to watch and get excited about.
"It's not the result we came for but we can walk away with our heads held high."
A tearful Ginn, 37, hinted he had rowed his last race, although he said he'd wait until the end of the year before deciding whether to stay on.
The victory maintained Britain's strong tradition in the event, stretching back to the days of serial gold-medallists Steve Redgrave and Matthew Pinsent. Redgrave congratulated the class of 2012 on the jetty as they climbed out of their boat.
"In the race today, I was waiting for it to go all wrong," Triggs Hodge said of the expectation on the British four. "We all sacrificed so much to achieve this huge honour. To sit here as an Olympic champion in front of a home crowd — I am humbled by this one."
The United States won bronze, two seconds behind Australia. It was a strong result for a crew racing in its first international and they managed to keep up with Australia and Britain for much of the race.
Sophie Hosking and Kat Copeland, who only started racing together at the start of the year, clawed back a fast-starting Greek boat to win the lightweight women's double for Britain 20 minutes later.
It was the third gold won by a female British crew at the Olympics. A British woman had previously never won more than a silver.
After crossing the line, Hosking buried her head in her hands. Copeland simply sat open-mouthed for seemed like an age, not quite believing the result.
"Our improvement over the past six months has probably been better than I could have hoped for," Hosking said.
China took the silver and Greece the bronze — both countries' only medals of an Olympic regatta dominated by the British for the second straight games.
"I am so pleased with our consistency and the ambition of our rowers," said David Tanner, British Rowing's high performance director. "If you can have people that have a great attitude in life, enjoy their sport and deliver, I think I'm a lucky man."