The UK's top mermaids are gathering this weekend in Northampton to battle it out for the national Miss Mermaid crown. But just what is it that motivates someone to don a tail and morph into a creature that is half-woman, half-fish? The BBC has dived into this unusual world to find out more.

'You cannot deny the sensuality of mermaids'

Image caption Grace, the current Miss Mermaid UK, went to the world finals in Egypt last year

"Like most young girls growing up, I always wanted to be a mermaid," says reigning Miss Mermaid UK, 25-year-old Grace Page, from Reading.

"I've always had a passion for singing, and, since a young age I've loved having long naturally blonde hair, and the sea fascinates me - so creating a career around actually performing as a mermaid just made so much sense.

"I was slightly apprehensive about being Miss Mermaid UK; after my minimal pageant experience I didn't know how I would fare against professional mermaids from around the world. But Miss Mermaid International really is different to anything you've ever thought about pageants. Whilst in Egypt [where the international finals are held] a huge focus of what we did was giving back to the community and raising awareness for marine conservation.

"We visited local schools, did litter picks at the beaches and removed litter from the sea and reefs and even put together some awareness videos.

Image caption Grace, who runs her own "hire a mermaid" business, says being a professional mermaid is a "huge investment"

"You cannot deny the sensuality of mermaids, but you can be both a magical, innocent inspiration for children and an alluring siren; it's all about how you hold yourself. My persona, and the aura I give off, is obviously completely different at a children's party than if I'm draped at the side of a pool for 'decoration' at a VIP event.

"If you want to be a professional mermaid it is essential that you train as a free diver and hold a free diving qualification. This will allow you to be able to hold your breath for longer periods of time and, more importantly, you will be able to do so safely.

"Becoming a professional mermaid is a huge investment - tails, training, insurance, marketing and so much more - not to mention the amount of time it takes out of your life if you're serious. As with all skilled and entertainment jobs you need to have a passion for it to succeed.

"Today's society is such a varied and colourful place; everyone wants to be able to express themselves in their own unique way.

"Does the human race need a mermaid beauty pageant? No. Is it a way to bring interest and magic back to a dark and difficult world? Absolutely!"

'People like to escape the daily grind'

Image copyright Paul Dale Image caption Hannah: "We have a big merfolk community"

"Miss Mermaid is about raising awareness of marine conservation, and bringing ocean creatures to life is a great way to talk about the impact of plastic and pollution," says Miss Mermaid Norfolk, 35-year-old Hannah Griffiths.

"It's about spreading some mermaid magic: making people smile but delivering a message from the deep too.

"People like to escape the daily grind or endless bad news stories to something magical and different. This crosses all oceans, and all oceans connect the world.

"We have a big 'merfolk' community who want to help protect the world's oceans."

'It is a great way to raise awareness about the cleanliness of water'

Image caption Natalia: "There always will be loads of opinions about whether mermaids are sexualised or innocent"

"For me, mermaids are the spirit of nature and dreams," says Miss Mermaid London, 32-year-old Natalia Suvorova. "You have to have some skills, but to become a mermaid you need to be a dreamer, get to the water with a tail, be a good swimmer, have fun and be yourself.

"Mermaids are fun, playful and friendly creatures.

"It is a great way to raise awareness about the cleanliness of water, and how people are affecting oceans of the world.

"There always will be loads of opinions about whether mermaids are sexualised or innocent, but as mermaids are magical creatures I think this helps kids and adults to believe in miracles."

'It is something I have never grown out of'

Image caption Gina: "I enjoy being a mermaid because I can be extra magical, unusual and different"

"I like being a mermaid because it is something that I have always thought of myself as," says Miss Mermaid Berkshire, 33-year-old Gina Coyle. "When I was younger I was always a mermaid in the bath and I had an Ariel Barbie doll I adored, and it is something I have never grown out of.

"I enjoy being a mermaid because I can be extra magical, unusual and different and it feels amazing being able to swim in my tail like the mermaid I am.

"Miss Mermaid UK is a complete step up from a usual pageant [with] the amazing charity funding we are doing to help with our oceans and sea life. It also helps people to become more aware that we mermaids are out there and anything is possible!

"I see the the image of the mermaid as I would a woman, except more magical. Mermaids have been depicted as a murderous siren but also as a strong-willed princess, and all in between.

"This sort of pageant has taken off around the world for the very reason that it is magical, different and positive. There are a lot of girls and boys dreaming of meeting a real-life mermaid and I think it's something that you don't grow out of.

"There is a permanent fascination and there always will be."

'Our differences were celebrated'

Image caption Sophie: "I've always wanted to be a mermaid or a fairy"

"As a child I always wanted to be a mermaid or a fairy because they felt delicate but powerful, which was how I wanted to be as an adult," says Miss Mermaid South Coast 20-year-old Sophie Loy.

"I don't immediately see the mermaid image as something sensual, I see it as magical and a way for children and adults to express themselves. But, as the mermaid's original image before the Disney recreation [The Little Mermaid] was of temptresses luring men off boats to their deaths, I think it could be seen as both.

"When I applied to be part of the pageant I never imagined that I would be accepted, let alone win a title.

"I am only 4ft 9ins (1.45m) and I am very alternative-looking which I thought would set me back quite far in the competition. But when I arrived to compete, everyone was so kind and accepting of everyone else, our differences were celebrated and we were encouraged to show our personalities on stage."

Mermaids - spanning centuries and cultures

Image copyright BOB CARE/AFP/Getty Images

The word mermaid is a compound of the Old English mere (sea), and maid (a girl or young woman)

The first stories appeared in about 1,000BC in Assyria, in which the goddess Atargatis transformed herself into a mermaid out of shame for accidentally killing her human lover

Explorer Christopher Columbus claimed to have spotted three mermaids in 1493 - historians believe these were probably manatees

Mermaids appear in British folklore as unlucky omens approaching doomed ships, or, at best, a sign of rough weather ahead

Hans Christian Andersen's fairy tale The Little Mermaid was first published in 1837, and tells the story of a young mermaid who falls in love with a prince she saves from drowning

The Fiji Mermaid was a famous hoax that featured in 19th Century showman PT Barnum's American Museum, which was actually the torso of a young monkey sewn on to the lower half of a fish

The Miss Mermaid UK final takes place at Billing Aquadrome in Northampton on Saturday. The winner will head to the Miss Mermaid International final in Egypt in November.