Is shopping with a Tesco Clubcard cheaper than going to Aldi or Lidl?

Shopping for a basket of groceries with a Tesco Clubcard or Sainsbury's Nectar card is still more expensive than going to Aldi or Lidl, new Which? research has revealed.

Tesco launched special Clubcard prices for members four years ago, and Sainsbury's followed with its own Nectar prices scheme earlier this year.

With food price inflation remaining stubbornly high, Which? put these loyalty prices to the test. Read on to find out how Sainsbury's and Tesco fared against their rivals - and whether they came close to matching Aldi or Lidl for a basket of groceries.

How do Clubcard and Nectar prices compare?

Every day in May, we checked the prices of 40 popular grocery items, including Heinz baked beans, milk and tea bags, at some of the UK's biggest supermarkets. 

Here's the full results:   

Aldi was still the cheapest, at £68.60 for our basket of 40 groceries, closely followed by Lidl. 

Shopping with a Tesco Clubcard was next cheapest - but at £72.89 it was still £4.29 more than shopping at Aldi. Both Tesco Clubcard and Sainsbury's Nectar prices (£75.51) did knock Asda (£76.45) off the top spot of the more traditional supermarkets though. 

• Find out more: supermarket price comparison over time

How much do Clubcard and Nectar prices save you? 

The regular price for our basket of items is actually more at Tesco than at Sainsbury's. But adding a Clubcard into the mix saves you more on a Tesco shop than a Nectar card does on a Sainsbury's shop - so when you factor in member-only prices, Tesco ends up cheaper than Sainsbury's.

In our 40-item basket, 12 products were available with a Clubcard price at Tesco but only one Sainsbury's item had a Nectar price. 

This partially explains the difference between how much you'd save with a Clubcard at Tesco (6%) and a Nectar card at Sainsbury's (2.1%). It's worth noting though that the Sainsbury's scheme is much newer than the Tesco one and has recently expanded to include more products.

These days, supermarket loyalty schemes operate in many different ways and our analysis only takes into account member-only pricing. We didn't look at the value of points collected, personalised vouchers or other rewards offered by loyalty schemes, which could be more valuable to you.

• Find out more: loyalty cards compared

What about the prices of individual products? 

Clubcard and Nectar prices did beat Aldi and Lidl on some individual items - but not all. 

The Cathedral City cheddar cheese in our basket was cheapest at Sainsbury's, where it was £2.75 on average with a Nectar card. It was £2.90 on average at Tesco with a Clubcard, but it was £3.25 on average at both Aldi and Lidl. It was most expensive at Ocado (£4.54).

The bacon in our basket was £1.85 on average with a Tesco Clubcard, £1.99 at Lidl and £1.82 at Aldi. It was cheapest - at £1.68 - at Sainsbury's, and that wasn’t even with a Nectar card.

• Find out more: best and worst supermarkets for shopping in-store vs online

How we compared prices for this test

We looked at the prices of 40 grocery items at eight major supermarkets every day throughout May, using an independent price comparison website.

At each supermarket, we worked out the average price for each item across the month; then we added them up to get an average trolley price. 

To keep things fair, for this research we included special offers, but not multibuys. If a member-only price applied to any of the products in our basket, it was included for the price for Tesco Clubcard or Sainsbury's Nectar. It wasn't included for the regular Tesco and Sainsbury's price. 

Our shopping list included branded items such as Heinz baked beans and Dolmio sauce, as well as own-brand products like apples and lettuce. Own-brand items won’t be identical across supermarkets, but we’ve used experts to ensure everything we’ve compared is as similar as possible based on a number of factors, including quality and weight.

• Find out more: how to spend less at the supermarket

Why Tesco Clubcard could be breaking the law

While shopping with a Tesco Clubcard will usually save you money, it doesn't always - and the fact that unit pricing (for example, the price per 100ml or 100g) isn't given on Clubcard prices means it's very hard for shoppers to work it out for themselves without pulling out a calculator. 

For example, when we looked at Clubcard pricing last month, we found a 910g bottle of Heinz top down squeezy tomato ketchup at regular price was cheaper per gram than a 700g bottle of the same ketchup on a Clubcard prices promotion.

We believe Tesco could be breaking the law by excluding unit prices on Clubcard offers, because in some cases it could be seen as a misleading practice under the Consumer Protection From Unfair Trading Regulations 2008 (CPRs).

We've reported Tesco to the regulator and are urging it to introduce unit pricing on its Clubcard prices as soon as possible to help hard-pressed shoppers find the best deals. 

• Find out more: Tesco 'could be breaking the law' on unit pricing

Affordable Food For All campaign

We believe supermarkets could do much more to help those struggling in the face of rampant food price increases. 

We want them to stock a healthy, budget-range products in their smaller convenience stores, and to commit to clearer unit pricing - especially on promotions and loyalty card offers - so that people can easily work out which products offer the best value.

• Do you want to see your supermarket take action to support people through the cost of living crisis? Sign our Affordable Food for All petition