Customers using a Tesco Clubcard to do their weekly food shop at Tesco instead of going to Aldi have been warned they are £551 a year worse off.

New analysis by consumer magazine Which? has found that Aldi was the cheapest supermarket in October, beating fellow German discounter Lidl, as well as the big hitters Asda, Tesco, Sainsbury’s, Morrisons and Waitrose.

Which? Analysis looked at a shopping list of a typical 62 items and found that they would set you back £111.66 if bought at Aldi in October.

Lidl was just barely behind, at 41p more for the same equivalent shopping basket, while at the other end of the scale, Waitrose was the most expensive with a £142.39 bill for shoppers.

Tesco shoppers with a Clubcard would pay £122.26 on average, or without a Clubcard, £125.09.

The Clubcard price means Tesco shoppers even with the loyalty card prices factored in would pay £10.66 more per weekly shop, or £551.20 over the course of the year if the same price difference was maintained on average.

Tesco has actually closed up some ground on Aldi, as the price difference was £652 in August.

This latest pricing analysis from Which? demonstrates that shoppers can make considerable savings on their groceries depending on where they buy their food, Which? Said.

For those using a Sainsbury’s Nectar card, October's shopping list of items averaged £125.93, which is £14.27 more than at Aldi and still higher than the prices at Asda (£125.26) and Tesco (£122.26/£125.09). Without a Nectar card, the same items at Sainsbury’s cost £130.79.

Harry Rose, Editor of Which? magazine, said: “Our latest monthly analysis once again sees Aldi crowned as the UK’s cheapest supermarket.

“In the lead up to the festive season, people are looking to cut costs where they can. Our analysis shows that by switching supermarkets consumers could save 22%, highlighting the advantages of shopping around where possible."