More than 400 swimmers braved freezing conditions to take part in the December Dip at Parliament Hill Lido.
Under blue skies and bright sunshine the swimmers plunged into icy water with temperatures as low as three degrees centigrade.
But the competitors on Saturday lifted their spirits with fancy dress, from Christmas trees to mermen, and were rewarded with mulled wine and mince pies.
They were cheered on by keen swimmer and star of BBC’s The Thick Of It Joanna Scanlan, and the North London Brass band, who played James Bond-inspired theme tunes, including Coldfinger, A View To A Chill, and Live And Let Die.
Jeremy Simons, chairman of the City of London Corporation’s Hampstead Heath Management Committee, which runs the event, said he was extremely impressed by those who took part.
He said: “I’ve never seen so many blue faces or heard such a cacophony of chattering teeth.
“The sheer resilience of these swimmers never ceases to amaze me.”
The event – now in its sixth year – also included a group of 40 extra bravehearts who signed up to the Arctic Adventurers challenge and swam two lengths (120metres) in the icy waters.
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