We asked Tesco, Waitrose, Sainsbury's, Morrisons, Ocado and Asda why they charge more than Aldi

Aldi is consistently hailed the UK's cheapest supermarket by Which?

Aldi has become increasingly popular in recent years due to its affordable prices. The budget retailer consistently tops consumer champion Which?'s "cheapest supermarket" list, which compares a basket of grocery staples bought from each of eight major UK supermarkets.

Commenting on this, Aldi's managing director of buying Julie Ashfield previously said: “We know that so many families across the UK are feeling the pinch, with many unsure of what the future holds. At Aldi, we’re dedicated to keeping costs low for our customers, without compromising on the high quality they’ve come to expect from us.

"We’re so happy to be named the UK’s cheapest supermarket yet again and are thrilled that our commitment to the lowest prices continues to be recognised.”

Its budget rival Lidl consistently comes in second place, with sometimes just pence between the two compared grocery shops. According to its website, Lidl focuses on "keeping our ranges simple so that we can avoid 'range overload' making the most of our space in store and keep costs down, helping you to shop efficiently."

So what about the other supermarkets?

For October, Which? found Aldi to be the cheapest again, with its average price for a basket of 62 grocery items coming in at £111.66. Waitrose was the most expensive, with its average price coming in at £142.39.

Here is a full list of Which's? average prices for the same 62 items from the major supermarkets it uses in its comparisons:

• Aldi - £111.66
• Lidl with Lidl Plus - £112.07
• Lidl - £112.33
• Tesco with Clubcard - £122.26
• Tesco - £125.09
• Asda - £125.26
• Sainsbury's with Nectar - £125.93
• Morrisons with More - £128.96
• Morrisons - £130.05
• Sainsbury's - £130.79
• Ocado - £135.47
• Waitrose - £142.39

Which? also compares supermarket prices for a "big shop". This consists of a trolley containing a "larger selection of 164 popular items - the original 62 plus 102 more". Aldi and Lidl are unable to be included in this price comparison as it includes "a wider selection of branded items, which were unavailable at the discounters."

For October, Asda was the cheapest for this longer list at £418.71. Tesco came in second at £422.54, but only when Clubcard discounts were factored in. The average "big shop" prices in full can be found below:

• Asda - £418.71
• Tesco with Clubcard - £422.54
• Morrisons with More - £428.32
• Sainsbury's with Nectar - £429.21
• Morrisons - £448.55
• Tesco - £449.99
• Ocado - £454.56
• Sainsbury's - £459.58
• Waitrose - £461.10

We asked Tesco, Asda, Sainsbury's, Morrisons, Ocado and Waitrose why their prices are often higher than Aldi's. These are the responses we received:

A Waitrose spokesperson said: “Our animal welfare standards, quality and customer service set us apart. We’re number one for animal welfare, with more awards from Compassion in Word Farming than any other UK supermarket. We also pay our farmers fairly - some of whom we’ve worked with for over 30 years.

“For example: we are the only supermarket to sell 100% free-range, own-brand fresh milk; all our own-brand fresh pork is British and outdoor-bred; and we have held CiWF’s Good Chicken Award since it began in 2010. We also work to exceptional levels of quality across all our products.

"Customers enjoy our innovative and exclusive products, such as our highly acclaimed Ottolenghi range, and recently relaunched No.1 range, which includes nearly 200 new products including honey smoked salmon, Wagyu rib eye steak, and pistachio croissants.”

A representative for Ocado said: "We offer the widest range of choice for customers to suit all types of needs and budgets. Since March 2023, and alongside multiple rounds of our Big Price Drop, the Ocado Price Promise matches customers' shop to Tesco.com on more than 10,000 products, including Clubcard prices."

Asda's spokesperson said: “Asda is consistently recognised as the best-value traditional supermarket in independent price comparison surveys including the Which? Big Shop’ price survey. This week we were also recognised as being the cheapest supermarket in The Grocer 33 basket comparison, despite this survey now including loyalty pricing.

“In addition, customers also get the added benefits of shopping at Asda rather than the discounters – such as household brands they love, great fashion and homeware from George, the best value supermarket fuel and cash rewards through the Asda Rewards app.

"The app gives customers money back into their Cashpot each time they shop, which they can use to reduce the price they pay at the till. In less than two years since its launch, Asda Rewards is now used by over six million customers who have saved more than £600m in total.”

Tesco, Sainsbury's and Morrison's were all approached for comment but did not respond by the time of publication.