Just short of 100 people braved near-freezing water to compete in the 155th Peter Pan Cup at London’s Serpentine.
The race, which began in 1864, sees members of the Serpentine Swimming Club swim a 100-yard course in Hyde Park.
This year’s race was won by Sakura Adams, 36, from London, who described her victory as “absolutely amazing”.
The competition acquired its name in 1903 when JM Barrie, who wrote Peter Pan, was a member of the swimming club and competed in the Christmas event.
Robin Hunter-Coddington, the president of the club, says between 80 and 90 members competed this year, up from around a dozen in the early 1990s.
Ms Adams, a 13-year member of the club, told the BBC it was a “dream” to win the cup – one that she is “over the moon” to have fulfilled.
The temperature of the water was around 5C (41F)- with the temperature outside around 8C.
But while some take pleasure from the competitive side of the event, all at the club stress it is the community of swimmers that keeps them coming back.
“It’s not only about the swim,” says Ms Adams. “It’s seeing the hundreds of people on the Serp-side cheering us on.
“This is more than a club, it’s a family and seeing everyone on Christmas morning is part of the family spirit, that’s why we come out.”
It is a family that requires commitment, however, with members having to compete in seven of the nine winter races to be eligible for the event on Christmas Day.
Johanna Allberg, who swam for the Swedish national team in her youth, came over to London to watch the race.
She had been hoping to be allowed to compete but was not allowed.
Her husband, Jhnar, says: “She swam in Sweden, I filmed her and sent the film to the club here and hoped she will get in but she didn’t.
“She wanted to come and do this anyway so she came and swam in the lake before the race.”
John Tierney, 54, from Kensington has been taking part in the race since 2007.
“You make friends,” he says. “Gradually you become more involved in the club, more involved in the people – it’s a social scene.
“We have a race every Saturday so in some ways it’s just another race for us – but it’s a very special one.”
After the race, each competitor is given a glass of port, while family members wander through the crowd handing out home-made biscuits.
Then, after the crowds have dispersed, members head indoors to exchange gifts.
“It’s very much a family club,” says Mr Tierney.
Elsewhere around the UK, people have also been braving chilly waters.
In Porthcawl, more than 1,300 swimmers sported superhero costumes and swam in icy sea water for the Christmas morning swim, now in its 54th year.
And in Bournemouth, bathers dressed up as Santa and his elves to take part in the annual white Christmas dip at Boscombe Pier to raise money for Macmillan Caring Locally.
Meanwhile, in the West Midlands, people took part in the Christmas tradition of jumping into Blackroot Pool, in Sutton Coldfield.
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