An astonishing final leg by Louise Watkin guided the British 4x100 metres medley (34 points) relay to silver in the final event of the penultimate night of the Aquatics Centre.
The quartet - made up of Heather Frederiksen, Claire Cashmore, Steph Millward and Watkin - were well down when she took over.
Still fourth at the final turn, Watkin overhauled both Russia and the United States to touch in four minutes 53.98 seconds.
Australia won as Jacqueline Freney claimed her eighth gold medal of the Paralympics.
Millward admitted missing out on gold was tough to take.
She told Channel 4 "We really did want the gold so we're all going to cry later. The gold we thought was within our reach and it was about point-nothing away which was a shame.
"I'm quite happy. Second is nothing to be upset about really."
Cashmore said: "It's fantastic. I feel privileged to be part of such a great team. My last swim tonight so it's pretty gutting. To be so close, to be points of a second off is hard but we did an amazing job and I don't think we could have done any more."
Frederiksen added: "We're a good solid team and we gave everything that we had. We're pleased with it."
And Watkin said: "I just wanted to finish it that so badly and I just wanted to bring it back for the team."