Marks and Spencer named best Supermarket in the UK – see the list here

The high street shop, which offers upscale food, received a customer rating of 78 per cent in the survey.

It was also rated five stars for appearance, customer service and quality of own-brand food and fresh produce. 

M&S chief operating officer and food managing director Stuart Machin said: “As M&S Food modernises to become a bigger, better, fresher food business and expand our appeal to enable more customers to shop bigger baskets, this is a welcome endorsement.”

Aldi was close behind with a 77 per cent rating and dropped to second place after being voted top in 2020.

View this post on Instagram

A post shared by Which? (@whichuk)

The discount supermarket was given five stars for value for money and named "cheap and cheerful", but was let down by long queues. 

Waitrose came in third at 75 per cent but suffered on low scores for value for money. 

Co-op was ranked worst, with customers noting it was "expensive", "always crowded" and had "long queues at checkout". 

A Co-op spokesman said: “Which?’s results are based on a sample of just over 200 people but each week more than 15 million shoppers overwhelmingly vote with their feet and visit our community stores.

Co-op was voted the UK's worst in-store supermarket (PA)

“They choose Co-op for quick and friendly service from our colleagues and to buy our award-winning food and drink and honest value range, which offers ethically sourced Fairtrade and 100% British meat products at a fair price to shoppers.”

The best online stores were Iceland (76 per cent), Tesco and Ocado (both 74 per cent). 

The results are based on a survey completed by 3,057 members of the public online in October, of whom 1,304 reported their online grocery shopping experience.

UK's best and worst in-store supermarkets revealed by Which?

1. M&S - 78%
2. Aldi - 77%
3. Waitrose - 75%
4. Tesco - 70%
5. Sainsbury's - 68%
6. Asda - 67%
7. Morrisons - 67%
8. Co-op - 61%