Great Britain won its fourth Olympic gold in 24 hours - and sixth in total - as Katherine Grainger and Anna Watkins triumphed in the women's double sculls.
Grainger, 36, was a silver medallist at three previous Games, with the world champions clocking six minutes 55.82 seconds.
Grainger's delight at winning gold
Australia took the silver and Poland the bronze. The gold came 20 minutes after the men's pair of
George Nash and Will Satch won bronze.
Alan Campbell then
won bronze in the men's single sculls.
Victory brought GB's second rowing success following
Heather Stanning and Helen Glover's win in the women's pair
Watkins and Grainger are now unbeaten in 23 races.
Since they teamed up in 2010, the duo have claimed two World Championship titles, bringing Grainger's total to six world gold medals overall.
"I never had a doubt. With 750m [to go] there was only going to be one winner. That is the story of the British medals so far at these Games."
The pair were the form crew coming to the Olympic regatta at Eton Dorney, comfortably winning gold in all three World Cups.
Grainger said: "It was worth the wait. Steve Redgrave promised me there would be tears of joy this time and there are. For both of us we knew we had the goods to perform and it was about delivering."
Watkins added: "I can't believe it. I've tried to keep my mind away from this moment. It was just another race but it was the right one."
Grainger and Watkins exploded out of the blocks to take an early lead ahead of the Australian crew of Brooke Pratley and Kim Crow.
Katherine Grainger reflects on her Olympic rowing gold
The Brits extended that lead to half-a-length by 500m and then two-thirds at half-way as the Australians hung on in second.
But it was at this point that Grainger and Watkins stepped it up a notch, upping their stroke rate and pushing ahead towards an expectant crowd that was already on their feet and going crazy with excitement.
Australia realised they were beaten as Watkins and Grainger pulled ahead with clear water and crossed the line to earn Grainger the gold she has been dreaming of since making her rowing debut in 1993.
Victory confirms Grainger, who dropped her shoulders with relief and looked up to the sky before raising her hands in celebration, as the most successful British female rower of all time.