British Naturism, the leading UK organisation for naturists, has urged its members to bathe naked wherever they please and has pledged to defend them if they are charged.
"Our view is that every beach in Britain is a naturist beach," said Rex Watson, editor of BN, the British Naturism magazine. "If any of our members choose to put that view into practice we will defend them in court ... as long as we are satisfied that they have behaved reasonably and there's been no indecent behaviour. We want to see pests and perverts firmly dealt with, but the difference between that and recreational social nudity is obvious."
British Naturism has appointed a lobbyist to campaign for reform of laws that restrict public nudity and is raising a fund for legal battles. Men bathing naked on a beach not specifically designated for naturism face prosecution under the 1824 Vagrancy Act, which makes it illegal to expose the "male person". Women can be charged under the Public Order Act.
The Nude Tolerance Campaign, quietly launched last November, is gathering pace as summer arrives and Britain's 25,000 naturists head for beaches and clubs.
A nude cross-Channel relay swim from Kent to France next month aims to raise the awareness of the general public, or "textiles" in the naturist jargon. "We are looking to generate acceptability of non-sexual nudity," said Roger Fowler Wright, research and liaison officer for British Naturism. "We want to increase the awareness of top-free and nude beaches in many parts of the world."
Britain has 170 clubs and 10 beaches where naturism is permitted, including Brighton and Studland Bay in Dorset. The most northerly is Cleat's Shore on the Isle of Arran. But naturists feel many are ghettoes. "It's difficult for a family or older people to trundle down a remote footpath to get to a beach," said Mr Fowler Wright. "As a result, these beaches can be selective in the type of person they attract."
Naturism is now big business. British Naturism has a website dotted with tasteful pictures of naturists at play and adverts for sun cream. British Naturism members enjoy discounts on ferry services, car rental and breakdown cover and can enjoy pounds 2,000 nude Caribbean cruises. Several mainstream tour operators, including Virgin, offer naturist summer packages.
Naturism goes back several hundred years, according to British Naturism's website. Wearing clothes to go swimming only became the norm towards the end of the Victorian period. "Sunbathing has only come into its own since the start of this century, and, like swimming, it is much nicer in the nude," the website says.
Mr Watson thinks bathing suits will go out of fashion within 20 years. "It's not an elegant garment and doesn't keep you warm after you get wet."
Naturism's revival began in the 1930s, when the French started nude bathing on the Ile du Levant. After the Second World War, so-called "free beaches" were authorised on the mainland. Now such beaches are found in almost every European country and nude beaches draw thousands of visitors to Spain, France, Greece and Croatia each year.