Keri-Anne Payne and Cassie Patten today produced an incredible show of endurance to claim silver and bronze in the 10km open water swimming.

Working to a cunning gameplan, the British duo swum as a partnership leading for almost all of the gruelling two-hour race only to be pipped for gold in the closing stages by Russian world champion Larisa Ilchenko.

It was a thrilling, blanket finish - with all three swimmers going full tilt for victory in the last 100 metres - and surely cements what is a new event at these Games on the Olympic programme for years to come.

Patten said: "Every part of your body is hurting. Your stomach is the size of a pea, because all the blood rushes to your arms, your body is saying stop but your head is saying come on keep going. The last kilometre felt like 20km, every time I looked up the finish seemed no closer."

World No1 Ilchenko initially set the pace at the Shinyi rowing lake but was soon overtaken by both Payne and Patten who then chose to dictate proceedings from the front.

Ilchenko, who inflicted a similar final-straight defeat on Payne at the world championships in Melbourne last year, then adopted her usual tactic of sitting on the feet of the leading pair.

But with 1 hour 32 minutes gone, Patten and Payne made a move to try to string out the race, upping the tempo in an effort to reduce the medal contenders.

Ilchenko, however, remained in touch, as did Brazilian Poliana Okimoto and Andreina del Valle Pinto Perez of Venezuela, as the bulk of the leading group re-formed. As the swimmers went round the final buoy, however, the speed increased again and Patten and Payne's pace-making had clearly taken its toll on much of the field.

With 250 metres to go, the medal contenders were whittled down to just four, with Germany's Angela Maurer joining Payne, Patten and Ilchenko at the front.

Maurer, though, was unable to match Ilchenko's burst of pace as the Russian pulled alongside the British pair. Payne fought back, matching her stroke for stroke until Ilchenko inched ahead in the final few metres to touch first.

Patten later claimed she was unhappy with some underhand tactics during the closing stages, saying: "I was quite annoyed, it's not sportsmanship when you pull on someone's feet." But the British team have not registered an official complaint.

Looking remarkably fresh after her slog, Payne said: "It's amazing what a silver medal can do for you!

"During the race, we didn't talk at all out there. We're best friends, we train together and we just kind of knew when to kick at the right time."

Payne and Patten's success raises British swimmers' total medal haul to five at these Games, after Rebecca Adlington's two fantastic golds and Joanne Jackson's bronze.

David Davies could add another medal tomorrow when he competes in the men's 10km race.