Aldi was the cheapest supermarket in July, according to the latest Which? analysis.
We compared prices for a trolley of 85 items, including food, drink and household essentials.
On average, shoppers would have paid £78.50 at Aldi, which narrowly beat rival discounter Lidl by just 96p.
Meanwhile, one mainstream supermarket was nearly £44 more expensive than Aldi for the same trolley of groceries. So which was it, and how do the other big grocers compare?
Here we compare supermarket prices across all the big names and look at the latest news in the world of grocery shopping.
Cheapest supermarkets vs the most expensive
Every day throughout July we checked the prices of 85 items, including own-brand products such as pasta, eggs and tea bags, as well as branded goods like Hovis wholemeal bread, to see how UK supermarkets compared.
Here’s how much our trolley cost on average:
At the other end of the scale, upmarket Waitrose was nearly £44 more expensive than Aldi, at £122.47.
Groceries with the biggest price differences included own-label prawns (where there was a £3.34 difference between Aldi and Waitrose) and own-label chicken drumsticks, which had a £1.48 difference. When it came to branded groceries, the biggest difference was in a popular pizza brand, which cost 75p more at Waitrose than Aldi.
Of course, price is just one factor when you’re deciding which supermarket to shop at. We also survey shoppers about quality, customer service, store experience, online deliveries and a range of other factors.
Find out more: Which? members rate the best and worst supermarkets
How do bigger shopping lists stack up?
We also compared a shopping trolley packed with 167 items (the original 85 plus 82 more). This included a greater selection of branded items, such as Branston baked beans and Flash cleaning spray, that aren’t always available in the discounter supermarkets – so for our super-sized trolley we haven’t been able to include Aldi and Lidl.
Asda, at £271.03, was by far the cheapest of the traditional supermarkets. It was a staggering £41.25 cheaper than the most expensive supermarket, Waitrose.
We can’t compare exactly the same items each month because products aren’t always available at every retailer, but Asda was also the cheapest major online supermarket when we checked in May and June.
Find out more: how to shop safely at the supermarket during the pandemic
How Which? compares supermarket prices
We tracked the prices of 85 items at the UK’s six biggest supermarkets throughout July.
For our larger trolley analysis we added a further 82 items for all supermarkets apart from Aldi and Lidl, where the products were unavailable.
Our shopping list combined branded items, such as Kenco Millicano coffee, Oxo stock cubes and Twinings English breakfast tea, with own-label products including pasta, lettuce and milk.
Of course, own-brand items aren’t exactly the same at different supermarkets, but we’ve used experts to ensure that the products are as comparable as possible, based on a range of factors including weight, quality and other industry data.
Using an independent price comparison website, we calculated the average price (including special offers but not multibuys) for each item throughout the month. We added those individual averages together to give an overall price for the trolley at each shop for the month.
Find out more: supermarket price comparison over time
Latest supermarket news
Supermarkets have frequently been in the news ever since the coronavirus outbreak, and July was no exception.
Wearing a face mask or covering is now mandatory for shoppers in England, Scotland and Northern Ireland, although different exemptions apply in each nation. Find out where and when do you need to wear a face covering.
Amazon announced that Prime members living in London and some parts of the Home Counties will now get free delivery on Amazon Fresh grocery orders of £40 and above. Amazon said it hoped to roll out the offer to other cities later this year, in a move which some commentators have hailed as a possible game-changer for the UK’s online grocery market.
Meanwhile online-only supermarket Ocado will stop selling Waitrose products and replace them with Marks & Spencer’s from 1 September, with the new M&S product range now live on the website for deliveries booked for next month.
Some 6,000 M&S products will eventually be available, replacing the 4,000 Waitrose products currently stocked by Ocado.
Find out more: supermarkets coronavirus latest