Bradley Wiggins has hammered the field to win the Olympic time trial and become Britain's most decorated Olympian with seven medals.
The Tour de France champion, who already had six track cycling medals including three golds, made a cautious start on the 44-km course starting and ending at Hampton Court Palace before powering home with an average speed of over 52 kph.
World champion Tony Martin of Germany took silver, a massive 42 seconds behind, with Briton Chris Froome claiming bronze, 68 seconds off the pace.
Wiggins, the first British rider to win the Tour 10 days ago, surpassed rower Steve Redgrave's six medals in an Olympic career that started in 2000 at the Sydney Games, where he took bronze in the Madison and team pursuit.
A few hours after Helen Glover and Heather Stanning claimed Britain's first London gold in the rowing pairs, Wiggins was in a class of his own, his perfect position on the bike unmatched by his rivals.
The powerful Martin was five seconds ahead of Wiggins at the first time check after 7.3 km, with Fabian Cancellara one second further behind in a close race with the top five riders within 10 seconds.
Luis Leon Sanchez's hopes of a podium finish vanished after just a few seconds when the Spaniard had to change bikes following a chain snap on the start ramp.By the second time check, after 18.4 km, Wiggins was 11 seconds up on Martin and 23 on Froome, after defending champion Cancellara of Switzerland had cracked following a strong start.
Cancellara suffered a bruised shoulder in the road race on Saturday and had pondered his participation until the last moment.
The course snaked through suburbia, past the famous horse race track at Sandown Park, close to the rugby stadium at Twickenham and even near Chelsea Football Club's training ground.