Soft drink sales at Thorntons' stores have risen almost 50% since the chocolatier began selling Coca-Cola lines at some of its stores.

Thorntons started selling the 13-strong range in 80 stores in June as part of a two-year deal with Coca-Cola. Under the deal, it replaced the limited range of drinks supplied by Britvic with a more extensive offer that included non-Coke brands Red Bull, Irn-Bru and Fruit Shoots.

Cold drink sales were now up 46% on last year, said head of trading and marketing Geoff Kershaw. The range, which includes Coke Zero, Fanta and Dr Pepper, had now been rolled out to a further 60 branches, he added.

"We sat down with Coca-Cola and said 'let's transform the range' and we also put new chillers into the stores," said Kershaw. "It has now been rolled out to even more stores we are seeing a fantastic sales uplift because we have a better range and competitive prices on the high street."

Thorntons has also rolled out a pick 'n' mix range, which comprises one third Thorntons lines and two thirds supplier Candy King's, to 50 stores in time for the school summer break.

It trialled the range in 11 stores in April to attract younger customers, and said impulse sales had risen 10%. "The school holidays is a key time for pick 'n' mix and we wanted to make sure we got it in as many stores as we felt were feasible to get the best of the trade from the summer break," said Kershaw.

Meanwhile, in an attempt to become a "gift purchase destination," Thorntons is trialling up to 150 greeting cards from supplier UK Greetings in 20 stores. "Greeting cards are a more radical departure for our customers so we want to make sure we get it right," said Kershaw. "We are such a time-pressured society and we can be the gift solution for customers I think there's real potential for that."

Thorntons was likely to sell wrapping paper in the future, he added.