Lidl has narrowly beaten Aldi to be named the cheapest supermarket of 2020, according to Which?.

The consumer comparison group tracked the price of 45 popular products including Hovis bread, Knorr stock cubes and free-range eggs in eight major supermarkets for at least 100 days between January and December 2020.

It calculated the average price of each item over the year and the total average cost of all 45 items – taking the weight and quality of items into account.

Which? said this is the first time it has included Lidl and Aldi in its annual study – which now includes own-label items as well as branded ones.

Lidl was the cheapest supermarket in the study, with the basket costing £42.67 on average.

An Aldi storeAldi was just 34p behind its rival Lidl in the Which? 2020 basket of items study (Peter Byrne/PA)

Just 34p put Lidl ahead of its discount chain rival Aldi, with the latter’s basket of items costing £43.01 on average.

Asda was the third-cheapest supermarket with the same basket of items costing £48.71 on average – a difference of more than £5 when compared with Aldi or Lidl.

Waitrose was the most expensive supermarket in the study. The average cost of the 45 items was £68.69 – around 60% or £26.02 more than a similar shop at Lidl.

The Waitrose website on a laptopWaitrose was the most expensive supermarket in the Which? study (Tim Goode/PA)

Which? also found stark price differences between popular own-label products at Waitrose and Lidl.

For example, Waitrose’s own-label cooked and peeled cold water prawns cost £4.60 on average, while the equivalent at Lidl cost £1.99.

Waitrose’s own-label six pack of very large free-range eggs cost £2.47 on average, whereas a similar product was nearly half the price – £1.27 – at Lidl.

Ocado was the second most expensive supermarket in the study, with its basket costing £66.83, while Sainsbury’s was the third-priciest retailer (£56.38).

Supermarkets had to adapt to changing customer behaviour in 2020 amid the coronavirus pandemic, with tight household budgets, panic buying and surging demand for home deliveries playing a part.

Which? said neither Aldi nor Lidl offer a full delivery service and they would have struggled to compete with supermarkets who ramped up their delivery service at the start of the pandemic, however Aldi offered food parcels for home delivery to help vulnerable people get essential goods.

Natalie Hitchins, head of home products and services at Which?, said: “Many households have been under financial pressure due to the pandemic, so getting value for money on their weekly shop has become more important than ever. Our analysis shows that customers do not have to pay over the odds for their groceries.

“Customers looking to save money this new year and cut down on the cost of their weekly shop should consider shopping around for the best prices.”

Here are the average costs of a supermarket trolley based on 45 products, according to Which?

– Lidl, £42.67

– Aldi, £43.01

– Asda, £48.71

– Tesco, £53.30

– Morrisons, £53.61

– Sainsbury’s, £56.38

– Ocado, £66.83

– Waitrose, £68.69