Team GB cyclist, Bradley Wiggins
Praise has poured in for cyclist Bradley Wiggins and the women's rowing duo after they scooped Britain's first gold medals of the Games.
Tour de France winner, Wiggins became the most decorated Olympian in British history, with a total of seven medals.
He won the cycling time trial after Helen Glover and Heather Stanning rowed to a historic victory, with the UK prime minister hailing the trio.
GB's Michael Jamieson has taken silver in the men's 200m breaststroke.
Team GB kept the nation waiting until day five of the Games for the first home gold medals, however there are high hopes for further podium finishes in Thursday's cycling.
After his victory, Wiggins, 32, cycled through cheering crowds gathered at Hampton Court, where he hugged his wife, Catherine and his children, Ben and Isabella.
David Cameron described the successes in rowing and cycling as a "golden moment for Britain".
Cameron said: "I think it's already a great Olympics, already a great start but this is really going to put rocket boosters on it for the whole country. I'm very, very excited."
Wiggins's grandmother Maureen Cousins was also at the side of the road as he crossed the finish line.
"I screamed when he won. It is a combination of delight and relief... We all think he is the greatest," she said.
Earlier, Glover and Stanning made history by becoming the first British women to win an Olympic gold medal for rowing.
Mr Johnson said an "historic triumph will be celebrated throughout the country today".
"It's an outstanding achievement and I'm sure it will spur on all our athletes in the medal stakes. It's fantastic - Go Team GB," he added.
Glover, 26, a former PE teacher from Penzance, Cornwall, had been rowing for only four years before securing gold with Stanning, 27, a Royal Artillery captain, from Lossiemouth, Moray.
They stormed home in front of cheering crowds at Eton Dorney after leading from the start of the women's pair race.