The idea could have been taken straight from the cutting room floor of box office smash 50 Shades of Grey.

But an acclaimed Highgate photographer’s stunning picture of naked Hollywood actress Helena Bonham-Carter straddling an enormous 27kg tuna is anything but pornographic.

The striking image by John Swannell, of North Road, is a visual love-letter to sustainable fishery and forms part of a charity campaign to raise awareness of the threat that over-fishing poses to marine life.

The 68-year-old said: “They are incredibly intimate pictures and she probably won’t do anything like that again and neither will I.

“The head of the charity said that he thinks they will become iconic because of what they are because no-one has ever seen anything like it.”

The renowned photographer has captured hundreds of famous faces on his lens, from world-famous celebrities to the Queen, in a career spanning over 40 years.

He has been taking pictures of Ms Bonham-Carter, of Belsize Park, for much of that time, and confided to the Ham&High that he jumped at the chance to be involved in the project when he heard that his “favourite” actress was involved.

The father-of-two said: “All these American actresses all blend into one another but she’s a one-off, she’s unique.”

The images of the 48-year-old actress are the latest in a series of portraits taken by different photographers for the Fishlove campaign, which aims to promote sustainable fishing practices.

Mr Swannell added: “If you hear about photographs of someone with a fish between their legs, you think 50 Shades of Grey or something pornographic but they’re just not.

“That’s not what we had in mind and it had nothing to do with that ugly stuff.

“It was very romantic and that’s what came across.”

Although Ms Bonham-Carter has a phobia of fish, Mr Swannell said it was not difficult to get her up close and personal with the bigeye tuna.

“She was worried about it,” Mr Swannell added. “She is phobic but she’s a great actress so she just became a professional and switched off her fears.”

The father-of-two also snapped actresses Dame Judi Dench, Zoe Wanamaker and Julie Christie for the project.

He said: “This project was very good for a photographer because it is a very visual thing to get fish with a naked girl.

“When you have a massive tuna and some of the most beautiful girls in the world, it’s a win-win situation.”

For more information, follow @fishlove2015 on Twitter or visit greatbritishoceans.org.