Simmonds clocked a time 5 min 18.69sec in the women’s 400 metres freestyle, knocking a second off her previous mark set at the London 2012 Paralympic Games.

The 21-year-old S6 swimmer, based at the National Performance Centre in Manchester, swam superbly as she moved away from the field in the early stages and maintained good pace to keep up with her record.

"I knew I had that in me," Simmonds said.

"I knew training was going really well leading into the competition but I am so happy.

"It’s great for me to get that time and great for my positivity.

"I’ll look back now and see what I can improve on and what did go well and what didn’t."

S10 swimmer Rosie Bancroft took silver with a time of 4:49.52, while bronze went to S6 swimmer Ellie Robinson after touching home in 5:48.72.

As for Northern Ireland's Firth, she lowered her own world record in the women’s 200m freestyle S14, clocking a time of 2:03.70 to take gold and reach the qualifying standard for Rio 2016.

"Words can’t really describe how I feel right now," said the 20-year-old, who won gold in the women’s 100m backstroke S14 at London 2012.

"I was praying throughout that whole race I was just hoping that I could do a good time and show people that I’ve come here to mean business."

Jessica-Jane Applegate took silver with a time of 2:05.63 to put her in consideration for Rio 2016, while bronze went to Chloe Davies in 2:13.26.

Tom Hamer set the qualification time needed for the Rio 2016 Paralympics Games in the heats and finals of the men’s 200m freestyle S14.

He broke the British record in the heats with a time of 1:57.27 and then clocked 1:57.49 in the final to secure gold.

Paralympic champion Ollie Hynd won the final gold medal of the evening after finishing the men’s 400m freestyle in a time of 4:24.69, just outside of his world record.

S7 swimmer Josef Craig won the silver medal in a time of 4:36.06 and bronze went to S13 competitor Stephen Clegg, who touched home in 4:19.17.

Clegg also set a British record in the heats with a time of 4:19.14.