The 50m and 100m Butterfly events are expected to be among the highlights, with two of the sport's heavyweights, USA star Jessica Long and South Africa's Natalie du Toit, defending their titles.

Tomorrow athletes in classes S5, S6 and S7 will compete in the women's 50m Butterfly, while classes S8, S9, S10 and S12 will race in the 100m.

Long , an S8 swimmer, said after a training session at the Aquatics Centre that she was 'not going to go down without a fight'. She is a veteran Paralympian, having won medals at Athens 2004 and Beijing 2008.

She said: 'My first time (at a Paralympic Games) I was 12. I had no expectations, but to come out with three gold medals was a great feeling.

'At 16 (in Beijing), I don't think I knew what I could achieve and the media were playing on what I didn't achieve, but still, four golds, a silver and a bronze isn't bad.

Coming to London makes all those hard practices and 5am starts worth it. I'm so happy and proud to be here.

Jessica Long

'Now I'm 20, I don't have anything to prove, I have my gold medals. I'm really content and happy. But I'm not going to go down without a fight.'

The opening day of Swimming competition will see 15 gold medals won, with Long contesting the women's 100m Butterfly S8.

Asked about the toughest part of competative Swimming, she said: 'The training. It's exhausting and hard. But coming to London makes all those hard practices and 5am starts worth it. I'm so happy and proud to be here.'

Du Toit, who swims in the 100m Butterfly S9, will be making her last Paralympic appearance and aiming to end her career on a high note.

The 28-year-old won five gold medals at both Beijing 2008 and Athens 2004 and will compete in seven events at London 2012.