The swimmers, from South Africa, Poland, Russia, Australia, Argentina, Italy, China, Bulgaria and Spain, appeared in Speedos on rubber ducks alongside the OneOcean expedition cruiser to swim in minus 1.4ºC waters.

Support staff and South African Emergency Physician expert Dr Sean Gottschalk were ready to perform rescue operations, but the swimmers withstood the extreme conditions.

The swim was a first-of-its-kind initiative by the International Ice Swimming Association and took place to raise funds for Madswimmer, a charity which organises world-first open-water swims in aid of children’s charities.

Steven Munatones of the World Open Water Swimming Association said the sport attracted individuals who were well prepared physiologically and psychologically to handle swims of up to 1km – and longer – in the cold air and water conditions under 5°C.

“After a decade of ice swimming, Barkai and his ice-swimming colleagues around the world have learnt a significant amount about how much the human body can acclimate to cold water, and how best to implement the rewarming process,” Munatones said.

Representing MadSwimmer, Jean Craven yesterday said achieving what they had done was no small feat.

“Raising only a few rand will not justify the effort. We hope the swim will inspire others to do their part to make this world a better place and give underprivileged children a chance to become the worthy citizens they deserve to be,” Craven said.