SASCHA Kindred was initially disqualified from competing in the final of the S6 200m individual medley final because a referee believed he was causing an infringement with one of his legs.
The gold medalist, who broke a world record to win the event at the Rio Paralympics, was initially barred from competing in the final after winning his heat.
British Swimming appealed the decision and Kindred as reinstated.
"One of the referees thought they saw a technical infringement relating to the leg kick during the fly," said Chris Furber, performance director at British Paralympic Swimming.
"Because of the way Sascha's impairement works, it means he's allowed to drag one of his legs through the water.
"There's a rule that allows him to do that and we pointed that out to the referees and they accepted that, so they reinstated him."
Former paralympic swimmer Liz Johnson said she was flabbergasted when she heard the news.
"He's such an accomplished 200m medley swimmer - he's 38 years old and has been doing this for 20 years," she said.
"We were like -,what could he possibly be disqualifed for?
"It said he had been disqualified for an infringement for his left fly kick because he only kicks with one leg.
"He's got cerebral palsy so the right hand side of his body doesn't work properly.
"I'm the same, so when we swim butterfly we have to keep that right leg as still as possible and control our stronger left leg so it doesn't pass the right leg and ends up like freestyle.
"The appeal went in and thankfully, after a long wait, he won the appeal and was back in the final."
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