Shoppers using a Sainsbury’s Nectar card are being warned they could be spending an extra £105 on their groceries per year.

According to the latest monthly analysis from consumer website Which?, a shopping list of 55 popular grocery items in November cost an average of £106.71 at Sainsbury’s for those using their Nectar card – £8.82 more than at Aldi, the UK’s cheapest supermarket. Over the course of a year, this could result in an additional £105.84 in costs.

Without a Nectar card,…