With an array of supermarkets available across the UK, and many offering their own unique loyalty scheme, it can sometimes feel impossible to know where's best to shop.

But for those looking for a bargain, they might be surprised to learn that Waitrose is cheaper than both Sainsbury's and Tesco if you don't have a Nectar or Clubcard, according to consumer champion Which?.

However, Asda was still named the cheapest supermarket for branded groceries for the third consecutive month, with its standard pricing trumping Tesco's Clubcard and Sainsbury's Nectar deals.

In an analysis of 240 popular branded items, including Nescafé Azera instant coffee and Mr Kipling Angel Cake Slices, Which? found that the shopping list came to £795.21 at Asda in April - cheaper than member-only prices at both Tesco (£821.67) and Sainsbury's (£850.39).

Morrisons, meanwhile, was five per cent pricier than Asda's average when using its More loyalty card (£838.15), and six per cent higher without one (£839.18).

Not only are the prices dearer than at Asda for shoppers without loyalty cards, but also at Waitrose (£895.28).

Waitrose was found to be the cheapest for several of the products assessed, including Dolmio Bolognese Sauce 450g, which was £1.50 on average in Waitrose compared to £2.60 at most other supermarkets, including Morrisons, Sainsbury's and Tesco for those without a loyalty card.

The consumer champion consistently finds Aldi and Lidl to be the cheapest supermarkets but given that they do not stock a sufficiently wide range of branded groceries, they were not included in the study.

Reena Sewraz, Which? Retail Editor, said: 'Our latest analysis shows Asda continues to offer the lowest prices on branded groceries without shoppers needing a loyalty card.

'At the same time, the gap between the cheapest and most expensive supermarkets is growing, with some shoppers paying up to 17 per cent more for the same basket.

'In some cases, consumers are paying double for identical products depending on where they shop and whether they have a loyalty card.'

A Sainsbury's spokesperson said: 'All examples in this report were cheaper on Nectar Prices and our customers know a good deal when they see one, with 85 per cent of sales involving a Nectar card.

'We are committed to delivering outstanding value on the products people buy the most, including over 700 products in the biggest Aldi Price Match on the market and our own‑brand value lines.'

A spokesperson for Tesco said: 'It's no secret that Clubcard unlocks the biggest savings at Tesco - but it's just one of the ways our customers get great value. 

'Our Aldi Price Match and Everyday Low Prices schemes ensure that all shoppers, including those without a Clubcard, enjoy competitive prices whenever they shop with us.' 

Big supermarkets came under suspicion of profiteering when food prices began rising in late 2021.

They began to offer discounted prices for those signed up to loyalty schemes such as the Tesco Clubcard or Sainsbury's Nectar, while non-members paid more.

Loyalty pricing discounts were seen by many as the 'true' cost of food, with the undiscounted price a steep markup for people not signed up.

In November 2024, the Competition and Markets Authority said its review of 50,000 loyalty priced products showed that 92 per cent offered genuine savings against the usual price.

That was despite 55 per cent of shoppers thinking 'usual' prices were raised to make loyalty deals more appealing, the CMA added in 2024.

The CMA's 2024 report found 'very little evidence' of supermarkets inflating their standard prices to make loyalty promotions seem like a better deal, but it did call on businesses to increase access to their schemes.