LONDON — The Valentine’s Day debut of “Fifty Shades of Grey” is providing a boon to an industry that rarely benefits from a big-brand film franchise: sex toys.

With the screen version of the erotic novel hitting theaters this weekend, purveyors of official merchandise are already experiencing a rush of demand in a market where only about 15 percent of products are branded.

“You have this recognizable brand for the mass of the population with the amount of publicity that ‘Fifty Shades’ has gotten,” said Marty Brochstein, senior vice-president of industry relations at the International Licensing Industry Merchandisers’ Association. “It’s a natural thing that it would attract attention and that it would bring a new element to this product category.”

Sales in Britain’s sex-toy industry are set to rise 25 percent to about 50 million pounds ($77 million) in the month leading up to Feb. 14 compared with the same period a year earlier, according to Lovehoney Ltd., Britain’s biggest online retailer of erotic merchandise.

Lovehoney, the owner of global rights to “Fifty Shades” pleasure products, had a record sales day last week, up 60 percent on the busiest day of 2014 as it handled more than 9,000 customer orders. Bluebella, a licensed creator of Fifty Shades-branded lingerie that sells at Asos and Selfridges &Co., said sales have risen 150 percent in the run-up to Valentine’s Day compared with last year.

The $2 billion sex toy industry expanded after the 2012 release of the novel that tells the story of college student Anastasia Steele’s sadomasochistic relationship with Seattle billionaire Christian Grey. With the movie debuting on Valentine’s Day amid protests from women’s rights groups that it glamorizes sexual and domestic violence, retailers are witnessing a surge in demand for handcuffs, whips and lingerie.

“People are really demanding the official branded ‘Fifty Shades’ items,” Lovehoney founder Richard Longhurst said in a telephone interview. “They don’t want a knock-off.”

Scarce branding in the adult toy industry is proving an advantage for the likes of Lovehoney, which expects sales to increase to more than 40 million pounds by the end of this year from 29.9 million pounds in the 12 months ended March 2014.

Lovehoney has sold more than 1.5 million “Fifty Shades”-branded items, according to Longhurst. In addition to its main range of 52 items, the company has teamed with upscale lingerie outlet Coco de Mer for its Red Room Collection of upscale bondage items, which was introduced last week.

Bluebella, a Bath, England-based lingerie producer, introduced a “Fifty Shades” gift line in 2013 and added a so-called black label collection in anticipation of the movie, featuring items such as its best-selling bandeau bra, described by founder Emily Bendell as a “show-stopping, bondage-inspired” piece.

“The market changed after the book and it’s been reinvigorated since the film,” Bendell said in a telephone interview. “People who haven’t read the book will see the film to see what the fuss is about, which will make them a bit more confident to indulge in some provocative pieces.”

While the novel expanded the sex toy market, the movie will likely tap a new type of customer: men.

“What’s going to be different from the book is that a lot of women are going to drag their partners along,” said Lovehoney co-founder Neal Slateford. “Guys will realize that if they go and see the film and all that sex looks fun, they can buy a ‘Fifty Shades’ product and have that fun as well.”