How is Samantha Cameron breaking into Hollywood? Elementary, my dear Watson

Smythson – the upmarket stationery firm that employs PM's wife – turns to product placement

Samantha Cameron was behind Smythson's Nancy bag and its red diary which is in a new Sherlock Holmes film, starring Jude Law and Robert Downey Jr (Rex Features)

It may be a quintessential English firm – an Old Bond Street address and the Prime Minister's wife as an adviser helps – but the upmarket stationery manufacturer Smythson has decided it is time to expand the empire and break into Hollywood.

Smythson has branched into product placement to help promote the brand globally. Samantha Cameron is a creative consultant after stepping down from her £400,000 full-time post as creative director.

The latest outing of stylish goods is in Guy Ritchie's new blockbuster Sherlock Holmes: A Game of Shadows. In the film, expected to be this year's festive must-see, the camera lingers over a red Smythson diary.

The company sent the Sherlock producers a number of diaries to choose from and Holmes himself would deduce that the diary's use is, at least, historically plausible. The fictional detective first appeared in print back in 1887, the same year that Frank Smythson opened his store at 133 Bond Street to supply "first class stationery, leather goods and cabinet work".

Smythson is also pursuing other placements in films and television shows. And the visibility of its goods across film and television has helped the company triple its profits this year to £2.4m. A spokesman for the stationers said: "We decide which films we feel are relevant and fit with our brand and history ... we have been making our books and diaries in pretty much the same way for over 100 years so they won't be that different now to how they were in late Victorian England."

In the film A Single Man, directed by the fashion designer Tom Ford, the actor Colin Firth left a note about the proper way to knot his corpse's tie on an engraved Smythson note card.

Smythson products were also supplied to Page Eight, the suitably classy BBC spy thriller written by David Hare starring Bill Nighy.

They have featured in the James Bond franchise and Gossip Girl, the hit US teen television drama, which relies heavily on product placement of designer goods. And Smythson said it is regularly approached by prop masters for items to borrow. "SamCam" herself has indulged in product placement for the firm. In an "at home" profile for US Harper's Bazaar she plugged a handbag, diary, silver pen and keyring, all available at Smythson.

It's not the first traditional English brand to use Hollywood to expand its profile. In Woody Allen's tennis film Match Point, Scarlett Johansson carried one of Mulberry's Roxanne bags. The ruthless traders in Money Never Sleeps, Oliver Stone's Wall Street sequel, brandished Dunhill accessories while in literature Bentley forced Aston Martin off the road to get James Bond driving a Continental GT in the new novel, Carte Blanche, by Jeffery Deaver.

Product placement has become a vital source of funds for the film industry, with companies spending about $1.8bn last year to get on-screen prominence for their brands. Ms Cameron was recognised as the driving creative force behind Smythson as creative director. Her achievements included the £950 Nancy bag, named after the couple's daughter.