Great Britain's LTA mixed coxed fours beat chief rivals Germany in a thrilling sprint for the line to win Paralympic gold.
David Smith, James Roe, Naomi Riches, Pam Relph and cox Lily van den Broecke added the Paralympic crown to the world title they won in Bled last year.
Britain's success in the mixed coxed four brought to a victorious conclusion an otherwise disappointing day for the host nation at Eton Dorney
Tom Aggar lost his Paralympic title and his five-year unbeaten streak as he finished fourth in the AS men's single sculls final.
Nick Beighton and Samantha Scowen, who only came together in the TA mixed double sculls last year, also had to settle for fourth after being edged out of the medals in a tight finish.
After two fourth-placed finishes, Britain's glorious summer of rowing was in danger of ending on a sour note to match the grizzly weather.
Britain's Olympians won four gold medals, two silver and three bronze to cement London 2012 as their greatest Olympic regatta of all time.
Aggar knew he faced the biggest challenge of his dominant career in today's final but to slip out of the medals altogether was unexpected and hurt him badly.
China's Huang Cheng, who smashed Aggar's world record in Friday's heat, and Russia's Aleksey Chuvashev set the early pace and Aggar was in touch at the 500 metre mark.
But Australian Erik Hollie produced a powerful second half of the race to take silver behind Huang and relegate Aggar out of the medal positions.
"I am absolutely devastated," said Aggar, who was paralysed from the waist down in a 2005 accident.
"It's hard for me to describe. I am devastated it wasn't my day. I went out hard to lead from the front and get control.
"The two guys to the left of me were really fast. When I tried to dig deep there was nothing there."
Beighton and Scowen had set themselves no targets beyond reaching the A final, which they did in impressive fashion through the repechage yesterday.
But having missed out on bronze by just two tenths of a second, their raw emotions matched those of Aggar's.
"We gave it everything and I am completely dead on my feet now," said Scowen, who was born with a short right femur.
"Fourth is the worst place. I would rather have finished fifth.
"It was really hard to come that close to a medal.
"I hope we made everyone proud."
Beighton lost his legs serving in Afghanistan less than three years ago and it was only last year that he competed in his first rowing race.
"Right from the (accident], I've wanted to seize life and this is the reward for that attitude. It has been a long journey but it is only just beginning," he said.
And so it came down to Britain's mixed coxed four to deliver the gold medal the Eton Dorney crowed craved.
Britain and Germany, who had set a new world's best time in the heats, seized control of the race from the outset and it came down to a head-to-head sprint for the line.
The Germans were marginally faster over the first 500 metres but Britain finished stronger, taking the lead in the third quarter of the race and eventually winning by nearly two seconds.