A new study has found that shopping at convenience stores such as Tesco Express, Sainsbury's Local and Morrisons Daily could cost you more than sticking to a big shop in a larger supermarket

Researchers also compared prices for customers with loyalty memberships such as Sainsbury's Nectar, Tesco Clubcard and Morrisons More. Morrisons customers face the biggest price difference as research found that consumers pay 21 percent more for the same groceries at a Morrisons Daily than at its supermarket.

Thousands are wasting up to £832 a year by shopping at the wrong supermarket. Which? compared the cost of 42 popular grocery items at convenience chains Morrisons Daily, Sainsbury's Local and Tesco Express against prices at their full-sized supermarkets.

An investigation has found that Tesco, Morrisons and Sainsbury's all charged more for a basket of shopping in their smaller local convenience stores.

A 500g bag of own-label fusilli was 31 per cent or 20p cheaper at a larger Sainsbury's supermarket at 65p instead of 85p. A medium white Hovis loaf cost 12 per cent more at both Sainsbury's Local and Tesco Express, and 14 per cent more at Morrisons Daily.

In total, the basket of 42 groceries would have averaged around £11 more at Sainsbury’s Local and £10 more at Tesco Express for loyalty scheme members, compared to their price