Food to go is one of the fastest growing categories sold by convenience retailers, according to new research, with snacks getting a boost as a result.

Sandwiches, sushi, salads and snacks purchased to go grew 6.6% in high street multiples (which include Co-op Food, Tesco Express, Little Waitrose and Sainsburys Local) for the year to 25 March 2017, boosting revenues by £36 million ($47.1m) for these stores, IRI says.

The market research firm claims retailers have capitalised on the British shoppers culture for convenience, expanding their ranges to include more innovative offerings than the lunch time sandwich.

Food to go sales in all retailers, including high street multiples, convenience multiples, petrol forecourts, travel outlets and independent convenience retailers, is worth £2.3bn and grew by 5% in the last year. Main store supermarkets dominate sales in food to go with sales of £1.5bn while convenience retailers traded around £900m in the last year. As the market has grown and retailers have seen how food on the go has the potential to bring shoppers into their stores, retailers have been experimenting with promotions including meal deals.

The sector now sells more than 1.4bn meals meaning that on average every person buys around 20 food to go meals a year.

Across all retailers, sales of sandwiches grew by 3.8% to £1.4bn and while they still account for most volume sales, it is baguettes, salads and sushi – all higher priced items – which are showing faster growth. Ready to eat salads, for example, grew 5.1% to £800m while sales of sushi grew by 12% to £100m.

Martin Wood, head of strategic retail insight at IRI, says, "Ready prepared food is a way of life for most time poor shoppers today who adopt a buy it when I need it approach to grocery shopping and who are eating out more.

"There are also some really good meal deals being offered that add a drink – with more convenience retailers also providing fresh coffee – and/or a snack to the sushi or sandwich lunch at a price that often works out a lot cheaper than all of the component parts. This is encouraging people to buy their breakfast, lunch or anytime meal on the way to work or home, boosting sales across not just the food to go category but also snacks and beverages too."

According to IRI, sales of snacks across all convenience retailers are also growing, with single serve salted snacks climbing 0.4% to £700,000,000. Collectively food to go, drinks and snacks are worth £7bn annually for all retailers.

However, independent convenience retailers (including symbol groups like Budgens, Londis, Spar, Costcutter and Nisa) who are more dependent on selling sandwiches, show much slower growth in the food to go category than the multiple convenience retailers (Tesco Express, Co-op, Sainsburys Local, OneStop, McColls and Little Waitrose).

All convenience retailers grew value sales of food to go by 5% in the last year (value sales of £865m), but this was driven by the high street retailers with growth of 6.6% to £584m and petrol forecourts and travel outlets up 2.9% to £185m. Independent convenience retailers showed a decline in food to go sales of 0.4% to £96m.

"There is a huge opportunity for independent convenience retailers to work with their wholesale and buying group partners to identify a broader range of food to go options. In this way, they can capitalise on these changing consumer behaviours," concludes Wood.