Ellie Simmonds sent the Aquatics Centre into a frenzy again this morning after she shocked herself by lowering her own world record in the heats of the SM6 200 metres individual medley at London 2012.

The Briton had already set a world record en route to the S6 400m freestyle title she successfully defended on Saturday but she was equally as impressive this morning.

The 17-year-old produced a blistering freestyle leg to make her rivals appear as if they were treading water to touch in three minutes 06.97 seconds, 1.13secs inside her own world mark from March when she became the first swimmer to set a global record in the Aquatics Centre.

The Swansea-based swimmer was completely taken aback and a second gold medal is a clear possibility tonight.

Simmonds said: "I wasn't going for a world record, I was actually going for the Paralympic record but I was just going in there to feel the stroke.

"When I walk out the crowd is amazing, that definitely gives me a big buzz. I just can't wait to race tonight.

"I am quite shocked with that time.

"When I was at the finish I couldn't actually see what (the time) was, I had to ask someone.

"I'm really pleased with a two-second PB in the heats.

"It's good to be on top form at the biggest Paralympic Games of my life."

China's Yang Yang also set a new world mark of 2:10.47 in the men's S2 100m freestyle, Ihar Boki of Belarus headed the S13 100m backstroke in a record 58.19 while Russian Denis Tarasov set a new mark of 25.92 in the S8 50m freestyle.

Ukraine's Olga Sviderska reduced the S3 100m freestyle mark to 1:45.34, Sweden's Maja Reichard dipped under her own SB11 100m breaststroke mark (1:28.51) and Jacqueline Freney of Australia set a new Paralympic record of 1:09.74 in the S7 100m freestyle.