Everyone who does their weekly shopping at Tesco is being warned they face being £401.44 worse off than customers who use Aldi instead over the course of a year.

New analysis from consumer magazine Which? found that Aldi was again the cheapest supermarket in November, testing a basket of 55 common food and drink items.

Lidl was just behind, 38p more expensive when using Lidl’s loyalty scheme or 45p without it.

But Tesco shoppers, even those who use a Clubcard to take advantage of Clubcard prices, would find themselves paying £401.44 more over the course of a year of weekly food shops on average if the same price differences were maintained.

Aldi shoppers paid £97.89 per weekly food shop, while Tesco customers using a Clubcard paid £105.61, a difference of £7.72 per week or £401.44 over a year.

Tesco shoppers without a Clubcard would pay even more, £108.45, according to Which?.

But in a test of a larger basket of goods which excluded Aldi and Lidl, as some products were not available at the budget retailers, Tesco came out the cheapest as long as you had a Clubcard, at £399.73, beating Asda by £9.63.

Perhaps unsurprisingly, Waitrose was the most expensive, costing £452.09 in the larger 159 item comparison - although Waitrose was also dearest on the smaller test at £123.32, roughly 25 percent more expensive than Aldi.

Harry Rose, Editor of Which? magazine, said: “Our latest monthly analysis once again sees Aldi crowned as the UK’s cheapest supermarket, however Lidl remains hot on its discounter rival’s heels.

“With Christmas just around the corner, people are looking to cut costs where they can. Our analysis shows that by switching supermarkets consumers could save up to 21 per cent, highlighting the advantages of shopping around where possible."