It was her second Commonwealth title after victory in Gold Coast four years ago, but, she admitted, far more unexpected.

"I didn't think I would be able to race this season," Tai told BBC Sport.

"I'm so grateful that Team England let me come here and compete."

Tai was born with bilateral talipes (club feet) which led to multiple operations as a youngster and increasing pain afterwards and required her to use crutches as a mobility aid.

However, the pressure on her arms left her requiring surgery on both elbows last year and as a result, she had to pull out of the Tokyo Paralympics.

While undergoing rehabilitation and struggling with her mobility, she asked once again about the possibility of having her right foot amputated.

"After the operation, I couldn't use crutches or self-propel a wheelchair, so using an electric wheelchair was my only option," she told the BBC's Access All podcast on the eve of the Games.

"I knew if I had the amputation I would have a better quality of life, if it went well. It made sense and it was the right time.

"It took me a while to realise how dramatic an option it was. I had mulled it over so much in my own head for many years so it was almost normal.

"As a Paralympian, I see amputees all the time with varying degrees of mobility but I know for everyone else it was a big deal."

Tai, who won seven golds at the 2019 Para-swimming World Championships in London, underwent surgery to have her leg amputated below the knee and, working with coach Dave Heathcock at Ealing Swimming Club, has had to relearn how to be an elite swimmer.

She made her international return in June's Para-swimming World Championships in Madeira, winning silver in the S8 100m freestyle to set her up for the Commonwealths.

And roared on by the Birmingham crowd, she started slowly and trailed Paralympic champion Tupou Neiufi of New Zealand early on before showing her strength.

"I've had so much to learn," she admitted. "I had to strip all my strokes back to the basics to make sure I am even in the water, but my stroke efficiency is better than it was.

"My coach reckons I can go faster because of that, so once we work on the technical stuff, I think my times could be quicker than before.

"My start can be better, but we don't know how I can balance best on the blocks and also my stroke into the turn keeps changing as I get fitter.

"I won relay gold in Rio which is awesome but I really want an individual title in Paris in 2024."

Analysis - Five-time Paralympic champion Ellie Simmonds on BBC Sport

Alice said coming into this race that she was going to race smart, and she did.

She kept up with the New Zealander and went for it in the last 50m and just gave it everything

After such a difficult year to get that gold medal is just fabulous.

The backstroke is her best event. She has a beautiful stroke and is naturally talented and even thought she won gold there are still things to improve.