The South African is arguably the world's best disabled athlete having won five gold medals at the 2008 Paralympics in Beijing and also earlier finished 16th in the open water swim at the Olympics, where she became only the fifth athlete in history to compete in both Games and the first amputee.

But Millward, a 28-year-old from Wiltshire now based in Swansea, believes that she can challenge Du Toit's supremacy.

Her confidence has been boosted by her performance at the International Paralympic Committee (IPC) World Swimming Championships in Rio de Janeiro last November where she won eight medals, including four gold.

She had earlier in the year also won five gold medals at the European Championships in Reykjavik.

Du Toit missed the World Championships but Millward expects to race her at the Commonwealth Games in New Delhi in October.

Millward said: "Natalie Du Toit has got all the Commonwealth and world records.

"I'd like to give her a good race and if I win it be wonderful.

"I don’t think I’ve raced her since the Paralympics and I want to show her who I am."

Millward represented Britain at international level and had hoped to represent Britain in the 2000 Sydney Olympics before being diagnosed with multiple sclerosis in 1999.

She then fought a six-month battle to get the expensive drug Beta Interferon, which reduces symptoms and stops the disease developing as fast.

Millward qualified for the Paralympics in Beijing, where she won a silver medal in the 50 metres freestyle in the S9 category.

But her performances in Rio have demonstrated that she has now moved to another level and hopes to maintain that progress in 2010, which is why she has left for the Sierra Nevada mountain range in Spain on a training trip.

Millward said: "I’m quite nervous about it because you have to see how your body will react.

"It’s supposed to increase the number of red blood cells you have which we’ll test before and afterwards, so it could help my fitness when I get back competing."