The popularity of the show has translated into a boom for U.K. retailers who have reported massive sales of arm-length gloves, fur capes, cravats and waistcoats that the Edwardian characters wear in the series. Even the old-fashioned liquor sherry has enjoyed a 15 percent rise in sales according to retail chain Marks and Spencer.
Devised and produced by Carnival Films, a British production company that was bought by NBCUniversal in 2008, the makers of "Downton Abbey" have been somewhat slow to capitalize on the show's success since it first aired on U.K. television in 2010. (Disclosure: NBCUniversal is the parent company of CNBC)
Carnival Films' managing director Gareth Neame defended the delay, however, telling CNBC the show had to be an assured success before launching itself as a brand, and that the Downton Abbey brand would launch in earnest this year.
"We'll be working across an entire range of products coming out this year. From fashion, apparel and homeware and furniture to wallpapers, beauty products and stationery," Neame, who is also the show's executive producer, told CNBC.
"Some of these things have been available since 2012 and we publish books and have made a music album, but the more complex products take time," he said, adding that there would be even more scope for merchandising in the future.
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"It's a very slow burn the moment you get into retail, it's extremely cautious, it has to test the established brand…No one wants to launch products if the show's going to be a flop," he told CNBC.
"In retail terms, the first series launched the program and the brand, the second year ratified it and the show didn't even hit its high point in the U.S. until this year when series three ended in the U.S…It's very rare for a British drama to have this much retail potential and merchandising value," Neame added.