Don't tell Hector Pardoe about the six-foot, 450lb jellyfish that have been flooding the coasts of Japan in their millions in recent years as a consequence of climate change.

The Wrexham 20-year-old, who will contest the 10km open water swimming event at the Tokyo Olympics, has had to overcome his fear of the translucent giants in order to carve a successful career away from the pool.

In fact Pardoe, who won the men's Olympic qualifier in Setubal last month to confirm his place, has revealed it almost put him off heading into the water at all.

Pardoe recalled: "When I qualified I got a load of messages, and one was from a boy I used to train with when we were about 12 years old.

"He sent me a photo of a training camp in Slovenia, and he reminded me of how when we would go in the sea and I was so scared that I couldn't even put my face in the water.

"We were talking about how far I'd come, from not wanting to even swim in the sea to now qualifying for a two-hour race in the sea at the Olympics."

Pardoe switched to open water in frustration after trailing other rivals in the pool and quickly found he adapted better to the changing conditions and courses. A subsequent decision to switch his training to France paid off as he continued his rise through the sport.

Pardoe will contest the men's 10km race at the Odaiba Marine Park on August 5, one day after team-mate Alice Dearing makes history by becoming the first black swimmer to represent Great Britain in the women's race.

Pardoe admits that while he bears little resemblance to the 12-year-old who was reluctant to put his face in the water, his underwater wobble remains – and that is not ideal in a country which boasts the Nomura's jellyfish, one of the biggest of the species in the world.

"I had quite a brutal experience with jellyfish in Malta in 2018 in the European Juniors," remembered Pardoe. "I was at the front of the pack going through the jellyfish first, and I got some nasty stings up my arms for which I've still got the scars.

"If I was just swimming recreationally in the sea I'd still be scared of jellyfish, but when I'm in an open-water race now I've got so much adrenaline and stuff, I don't really think about it."