The 40-year-old was one of the most experienced on the British team having competed at four Paralympic Games from 2008 to 2020, winning 10 medals.

Millward was prolific at Rio 2016, winning two gold, one silver and two bronze medals.

Prior to that, she won four silvers and a bronze at London 2012.

"This is a quick but heartfelt message to say that I am retiring from international swimming and I wanted to thank you all for everything you have done for me," Millward said.

"Aged eight, I had a dream of winning an Olympic Gold medal and by 16, having just become the National 100m Backstroke Champion and looking likely to qualify for the Sydney 2000 Olympic Games, everything in my world was beyond terrific.

"However, this world was soon shattered for soon after and, with no warning, I became ill.

"Rather than travelling to Australia, I was diagnosed with multiple sclerosis.

"Fast-forward 21 years, and I have just celebrated my 40th birthday, having returned from Tokyo, where I competed in my fourth Paralympic Games.

In addition to her medals, Millward was also awarded an MBE in the New Year's Honours List in 2016 for services to swimming.

"I have been awarded an MBE and given the freedom of my local town, Corsham.

"I was recently appointed a Deputy Lieutenant (Wiltshire) and I am a patron and ambassador to nine charities.

"It is all quite difficult to process but I am honoured, humbled and proud in equal measure."

Millward joins fellow swimmers Ellie Simmonds and Ellie Robinson in confirming they would be hanging up their googles following Tokyo 2020.