Duchess of Cambridge Kate Middleton has helped increased sushi sales, making it one of Britain’s most sort-after snack.

Kate and her sister, Pippa Middleton, are massive fans of the Japanese raw fish and have helped rocket sales of the delicacy by more than 20 per cent in the past year alone, according to retail analysts AC Nielsen.

UK’s largest supermarket chain, Tesco, says its sushi snacks now outsell both the popular ploughman’s – made with cheese, pickle and salad – and tuna and cucumber sandwiches which have always been front runners.

Kathryn Bettles, Tesco sushi range developer, said: “Sushi has now become a mainstream popular snack for many people around the UK, taking on some of our most successful sandwiches.

“Over the last five years it has been steadily growing in popularity.”

Sushi is made up of raw fish – such as salmon – seaweed and rice, and is rich in omega 3, vitamins and minerals. It is also a healthy alternative to other fatty snacks.

Earlier this year, Kate – who married future king Prince William in April – was seen enjoying the delicacy with her parents at Yo! Sushi restaurant in London department store Harvey Nichols. Since then the trend is continuing to grow among royal enthusiasts.