Back in 2003, Hall was lining up at swimming meets alongside Olympic champion Rebecca Adlington as part of British Swimmingâ€™s world-class potential programme.
At 11, he was ranked No1 in all freestyle distances, 50m through to 1500m and before long his ever-increasing medal tally caught the eye of tough-talking Australian Bill Sweetenham, who coached Britain for seven years until 2007.
â€œI thrived off winning, beating records and the attention. I was fascinated with human evolution and progress,â€ Hall says. â€œI was looking up to my hero Mark Foster and Olympic gold medallists, saying that I would one day be there.â€
However, Hall claims Sweetenham â€œmeddledâ€ with his freestyle technique. â€œFrom an enjoyable 14 hours per week, it ramped up to 20 hours and if you didnâ€™t do it, you would be chucked off the squad,â€ he recalls.
â€œThere was so much pressure at a young age. It was Sweetenham who bullied the swimmers, coaches and ruined it for 90 per cent of the swimmers there. I hated it.
â€œI genuinely believe that if he hadnâ€™t come along I would be an Olympic gold medallist, I seriously do. I was that determined.â€
Sweetenham was later cleared of bullying allegations, although one report suggesting 13 Olympians retired because of his no-nonsense approach.