Swimmers have to get medical advice before entering the race
Hundreds of swimmers have braved the cold and plunged into sub-zero temperature waters in south London.
The hardy souls were participating in the fourth UK Cold Water Swimming Championships at Tooting Bec Lido.
The event tests the endurance of the enthusiasts as many trained swimmers take the plunge alongside novices.
Participants have to compete in various categories which involve swimming the entire 90m of the pool, said to be the UK's largest unheated open air pool.
The event was open to everyone and races are based on age groups from under-19s through to the 80s and over.
The event tests the endurance level of the swimmers in sub-zero waters
Competitors must obtain medical advice before entering cold water, and wear a silicone swimming cap.
Organiser Margie Sullivan, of the South London Swimming Club, said: "We have got a load of very hardy souls down here swimming at Tooting Bec Lido in water that is probably about 1 or 2 degrees centigrade, near freezing.
"It feels like there is a heat inside you that is going to radiate through your body and you just feel fantastic, pure elation".
"Being fast isn't a part of what its about, its about being able to get into that cold water and getting to the other side, because that's the difficult bit," she added.
Bob Picknow, from Tunbridge Wells, has been participating in the event and competed in the 50 to 59 age group.
He said: "I won't stop doing it now because when you've actually caught the bug you really start getting the feel of it."
The inspiration for the challenge came after a group from the South London Swimming Club took part in the ice-swimming championships in Oulu in Finland in February 2005.