The Outdoor Swimming Society, which was founded to encourage people to rediscover the joy of swimming in Britain's seas, lakes, rivers and lidos, has opened registration for two "Breastrokes" sponsored swims to raise money for breast cancer research at Cancer Research UK.
In its manifesto, the organisation, which says "water needs no roof", commits to liberating swimmers from their "chlorined captivity" and to "embracing the rejuvenating effects of cold water and undertaking to strip and dip wherever (they) can".
It also offers safety advice on outdoor swimming, such as never swimming alone and keeping the head well above the waterline when swimming breaststroke in rough conditions to avoid swallowing water.
The society, which says outdoor swimming is making a comeback after enjoying its heyday in the early 1900s, will raise money for different causes each year.
Kate Rew, the society's founder, came up with the idea after her mother recovered from breast cancer through taking part in a CRUK drugs trial.
"Many charity challenges are really tough, but swimming outdoors is beautiful," she said.
Participants must pay a registration fee and pledge to raise £200 in sponsorship. The first swim, on 3 September, will be a 2,500m event at Lake Windermere in Cumbria, and will cost £30 to enter.
Those wanting to take part in London can join in a much shorter, 500m swim at the Serpentine on 30 September - this one costs £20.
Keen swimmers can sign up at www.outdoor swimmingsociety.com.
