Kadeena Cox won Britain's 14th gold medal at the World Para-athletics Championships in the women's T38 400m.
Cox beat runner-up Japan's Yuka Takamatsu by almost six seconds for her second medal of the championships, having won 200m bronze.
The 26-year-old, who has multiple sclerosis, won gold medals in cycling and sprinting at the Paralympics in 2016, where she claimed the 400m title.
Briton Paul Blake, a gold medallist at Rio 2016, was fourth in the T36 400m.
British T20 pairing of Steve Morris and James Hamilton both progressed to Saturday's 800m final, with Morris winning his heat and Hamilton second.
Great Britain have won 30 medals in London, one short of their tally of 31 at the 2015 Worlds, and have surpassed the total of 13 golds from two years ago.
"I am absolutely shattered, it was a very painful run but it meant a lot, this one was a good one and it was for a lot of people," Cox, who has the 100m to come on Saturday, told BBC Radio 5 live.
"We are here in London and the crowd is amazing, I may have got a bit carried away in the first 200m, I got the win, a bit off the time I wanted, but I got the win.
"I came out here to win the 400, the 200 was because I had a lack of races and I was a bit gutted in that race but here it has come together."
Cox became the first Briton to win a medal in two different sports at a Paralympics since 1988 with three medals in Rio - a gold, silver and bronze in athletics and gold in the cycling C4-5 time trial.
This is her third world title, having won the 100m in the T37 classification and relay gold in 2015, and it comes in year in which her funding was stopped briefly while she competed in winter sports game show The Jump.
But she was seriously lacking in competition in a race that she led from the gun and won by a huge margin.
Britain's 11-time Paralympic champion and BBC Radio 5 live summariser Baroness Grey-Thompson wants to see more depth in the T38 classification, which is for athletes with cerebral palsy or similar neurological conditions.
"It is another one of these developing classes and in terms of how she ran, she ran really well," she said.
"I would love to see the countries that don't have people in these classes go out and develop people to compete."
Blake, 27, who has cerebral palsy, had already finished eighth in the 200m and has the 100m to come on Saturday.
It will be his last opportunity to take a medal from these championships, having won 800m gold at the 2013 and 2015 Worlds, and 400m gold in 2011.