Aldi pipped rival discounter Lidl supermarket to the post of cheapest supermarket in November by just 87p, the latest monthly analysis by Which? has revealed.
We compared prices for a basket of 23 grocery products. On average, shoppers would have paid £24.64 at Aldi or £25.51 at Lidl, which is just 3% more.
At the other end of the spectrum, meanwhile, the priciest store was over £10 more expensive than Aldi for an equivalent basket of groceries.
Read on to find out how Asda, Sainsbury's, Tesco and more fared, and what's going on with grocery shopping prices in the run up to the festive period.
Each day throughout November, Which? checked the prices of 23 items - including own-label products such as eggs and milk and branded items like Warburtons wholemeal bread - to see how UK supermarkets compared. Here's how much our basket cost on average:
Groceries with some of the biggest price differences included Maltesers, which were £1.44 more expensive at Waitrose than Aldi (£2.93 and £1.49 respectively) as well as PG Tips tea bags, which had average prices of £3.48 at Aldi and £4.93 at Waitrose - a £1.45 difference.
But price is just one element to consider when you're deciding which supermarket to shop at. That's why we also survey shoppers about supermarkets' product quality, customer service, store experience, online deliveries and a range of other factors to reveal the each year.
We also compared a trolley packed with 72 items (the original 23 plus 49 more).
This was made up of a greater range of branded products, such as Heinz baked beans and Kellogg's Crunchy Nut honey and nut clusters, which aren't always available in the discount supermarkets. Therefore, for our bigger trolley, we haven't been able to include Aldi or Lidl.
Asda, at £136.31, was the cheapest of the traditional supermarkets in November. It was £20.82 (Or 15%) cheaper than the most expensive supermarket, Waitrose.
Prices at second-cheapest Sainsbury's weren't much more than at Asda this month: our trolley came to £140.96 at Sainsbury's. And there was only £1.40 between Tesco's £148.68 trolley and Morrisons' £147.28 total.
We can't tot up prices for exactly the same items each month because products aren't always available at every retailer, but Asda has now been the cheapest mainstream (non-discounter) supermarket for 23 consecutive months, having claimed the crown every month since January 2020. We'll reveal whether it's made it for the full two years in January.
We check the prices of hundreds of grocery items at eight major supermarkets every day throughout the year, using an independent price comparison website.
For our 'cheapest supermarket of the month' analysis, we calculate the average price for each item at each supermarket across the month, and add the averages up to get an average trolley price for each store. We include special offer prices but not multibuys, to keep it as fair as possible.
Our shopping list combines branded items such as Innocent orange juice and McVitie's digestives with own-label products including onions and milk. Of course, own-brand items aren't exactly the same at different supermarkets, but we've used experts to ensure that the products are as comparable as possible based on a range of factors including weight and quality.
Prices in shops rose by 0.3% in November 2021 for the first time since May 2019.
This compared to a 0.4% fall in October, according to figures from the British Retail Consortium (BRC) and data provider Nielsen.
Food price inflation accelerated to 1.1% in November 2021, too, up from 0.5% in October, and above the 12 and six-month average price growth rates of 0.1% and the highest inflation rate since November 2020. Fresh food inflation, meanwhile, increased to 1.2% in November up from 0.3% in October - the highest inflation rate since August 2019 - while ambient food inflation was 0.9% in November up from 0.8% in October. This was the highest rate of increase seen since April 2021.
Helen Dickinson OBE, chief executive of the BRC, said: 'November saw overall year-on-year prices increase for the first time in two and a half years, driven by rising food prices, and non-food deflation slowing. The impact of labour shortages, rising commodity prices and transportation costs have now very clearly taken their hold on consumer prices.
'With food prices rising, and particularly fresh food - which saw the highest inflation since 2019 - we may find some of our Christmas shopping a little more expensive this year. Food was also affected by a rise in global food costs where certain staples, such as vegetable oil, have doubled in price in the past two years.