What's it like to go to a family nude swimming session?

"At my first event, I slung a towel over my shoulder and went down for breakfast - naked."

Events organiser Pamela Fraser, 27, went to her first naturism event 14 months ago. She's been to 20 since.

Spa days, archery, yoga, cider-tasting and even a Fawlty Towers-themed night with actors playing Basil, Sybil and Manuel - all without an item of clothing in sight.

She describes the first time she got naked at a large gathering as a "non-event', adding "you soon realise people aren't interested in what you look like."

On Saturday, she'll join around 300 others of all ages, paying up to £21 for a skinny dip at Blackpool's Sandcastle Water Park.

"It's no different to going swimming with your costume on," Pamela believes. "A lot of female costumes don't hide much anyway."

So why take your clothes off?

"The whole idea is you're stepping back from the stress of life and the feeling that you have to fit into a certain mould."

"You wouldn't take your work clothes with you when you go on holiday and when you go home you probably get changed.

"Sometimes I get in from work and take all my clothes off - that's me saying this is now my free time."

Pamela is one of 9,000 people who pay about £44 a year to be members of the British Naturism (BN) organisation.

It offers advice and support and organises days out and festivals - including NudeFest, NKD and Nudestock - across the UK.

Pamela had always found it "more comfortable" to be nude at home but began going to events after spotting a BN magazine while at work.

"Everyone looked so happy - it was really inviting and it looked like there was so much going on. I thought, 'How have I got to 25 and not heard about this?'"

"There are some people who think nudity and bottoms are really funny. But I think laughing at someone who has nothing on is rude."

Upcoming trips include two more swimming days in Stoke-on-Trent and Poole, naked-dining near Stevenage, a pétanque tournament in Norwich and a two-hour boat trip in Scotland.

But Saturday's swim has caused concern for some.

About 50 people signed a petition calling for Saturday's swim to be cancelled or to be made over-18s only. Children, it said, would be "at risk of being subject to abuse by sex offenders who may slip into the organisation unnoticed".

One self-employed woman who plans to go to the event says she has no concerns about taking her children.

The 38-year-old - who asked not to be named - said: "I do understand where people are coming from in asking 'how can it be safe?'. It's just like any area of life, you always want to protect your children.

"But some don't have an understanding of the community. I've never once been worried about anything. When you're in something, it can often be very different to what others might perceive from the outside."

Her family found naturism about eight years ago, she says, when they accidentally ended up on a nudist beach on holiday. After enjoying the "relaxed atmosphere" they were keen to find similar experiences elsewhere abroad and, finally, in the UK.

"The girls love the swimming events - the queues are much better than if you go on another day, " she said, speaking ahead of Saturday's swim.

"There are some times when my daughter might say she wants to wear her bikini bottoms - and that's fine of course. Then she gets there and they decide she doesn't need them. It's their choice to go naked if they want to but, if not, that's also fine."

And she thinks there might be an even greater benefit than queue-jumping.

"My eldest daughter's friends are becoming more concerned about what they look like but she says she doesn't. That really touches me as a parent: that she hasn't really taken on that societal body-conscious stuff.

"How can naturism not have influenced that?"

BN event organiser Mark Walsh says many new members are introduced to the group through other events aimed at "free and earthy" vegans, yoga fans and camping enthusiasts.

"Some of our events are open to non-members, which brings in new people," he said. "Otherwise we just do marketing the same as any other organisation - but mainly in nudist circles."

On Saturday the group will also attempt to break the Guinness World Record for the most people on a rollercoaster at Blackpool Pleasure Beach. The record was set in Southend in August 2010.

People can join on the day but are asked to sign-up via the website in advance.

"Our members are our life-blood," says Mr Walsh. "And when they get a crazy new idea, it's my job to make it happen."