A time of 3:14.051 saw them demolish the United States and beat their own world best by half a second hours after bettering themselves from yesterday's heats in the semi-final.
Danielle King, Laura Trott and Joanna Rowsell had stormed to a time of 3:14.682 to advance over Canada into the final at the Velodrome.
They added the Olympic crown to the world title they already owned and took Britain's tally of golds on the track to four with a sixth track cycling world record for Britain.
Trott, at 20 years and 102 days, became the youngest gold medallist in women's events in cycling track at the Olympic Games, breaking the record of Australia's Anna Mears when she won the 500m time trial at Athens 2004.
Such was their searing pace that at one stage it looked as though the British team, unbeaten in 2012, might even reel in the US trio of Sarah Hammer, Dotsie Bausch and Lauren Tamayo.
The Americans avoided that humiliation but still finished more than five seconds back in the 12-lap event.
Canada claimed bronze with victory over Australia while New Zealand saw off the Netherlands in the 5/6 place race.
Australia had the world record in their sights in their semi-final match against the United States but they cracked in the final kilometre, losing by 0.082 seconds.
Harlow-born Trott was delighted to have realised her own Olympic dream and do it in yet another world best time.
“It’s mad I can’t believe it,” said the 20-year-old. “I feel dead emotional right now – it was my dream, it’s been my dream since I was eight and we’ve just gone and done it.
“I don’t think we expected it, I think maybe here we expected it one of the rounds but not in every single ride that we did. We just can’t believe it really.”
And 21-year-old King confirmed the family atmosphere within the team helped them through to making history.
“We are like sisters and I couldn’t have done it without them,” she said. “They were absolutely incredible and I can’t believe we’ve done it and its absolutely amazing.”
Manchester-based Rowsell admitted the vociferous atmosphere inside the velodrome helped the trio through the tough final part of the race.
“I could tell by the noise of the crowd that we were winning,” she said. “We didn’t need Paul walking the line because they were shouting so loud and it really spurred us on in the last kilometre.”
There was a routine heat victory for Jason Kenny in the men's individual sprint over South Africa's Bernard Esterhuizen.
Kenny recorded a time of 10.363 seconds to reach the quarter-finals, while the South African's second chance of advancing also escaped him with Azizulhasni Awang of Malaysia and German Robert Foerstemann taking the two available spots via the repechage.
France's Bryan Coquard took a halftime lead in the Olympic omnium thanks to a commanding win in the elimination race on Saturday.
Coquard was the last man standing among 18 riders, with the last one to cross the line every two laps being eliminated.
The Frenchman used his amazing jockeying and positioning abilities to win the third of the six disciplines held over two days, beating Italian Elia Viviani, who is second overall three points behind.
Britain's Ed Clancy, who had destroyed the opposition by clocking the fastest time in the 250-metre flying lap to take the early lead, dropped to fourth overall seven points behind Coquard.
Coquard had limited the damage in the second event, the points race, which is supposed to be his weak point.
Australian Glenn O'Shea was third overall.
The omnium is a test of all-round skills over two days in six disciplines: a flying lap, 30-km points race (20 km for women), elimination race, 4-km individual pursuit (3km), 15-km scratch race (10km) and one-kilometre (500m) time trial.
The last three events will be held on Sunday.
Points are added up depending on placing in each event and the rider with the lowest points score wins.
- Laura Trott
- Joanna Rowsell
- United States