Tesco may have renamed itself ‘Britain’s biggest discounter’ but it is still not Britain’s cheapest supermarket.

However you cut it, Asda remains the UK’s cheapest supermarket overall, according to our data. Not only has it won the annual The Grocer 33 award 11 years running, but it has topped the weekly survey more times than its rivals put together so far this year.

By contrast, Tesco’s average item price in The Grocer 33 database puts it in third place, well behind rivals Asda and Morrisons.

But, as Sainsbury’s win on The G33 price survey this week shows, Asda cannot boast a clean sweep. Consumers could save even more on their weekly shop if they chopped and changed stores depending on the category – and the reality of who emerges cheapest on what doesn’t always match the retailers’ hype. Morrisons, which plays up the value credentials of its Market Street fresh foods and deli counter offering, is beaten into second place on price (albeit narrowly) by Asda across a range of fresh food categories.

Over the past four weeks, Asda’s fruit and veg items have boasted an average price of £1.04 compared with Morrisons’ £1.06. It’s a similar picture in dairy and bakery with Asda’s prices of £1.80 and £0.86 undercutting by a whisker Morrisons’ £1.81 and £0.87. Only in meat, fish and poultry, has Morrisons’ £6.76 average item price beaten Asda’s £6.86, and by a reasonable margin. Beyond the category, ‘first for fresh’ Morrisons also trumps its rival in alcohol and health and beauty, with £6.56 and £2.19 averages versus Asda’s £6.70 and £2.19. In the deli sector, meanwhile, Sainsbury’s comes out on top, with an £1.93 average price compared with Morrisons’ £2.

However, Morrisons is far from the only retailer whose claims are not always borne out by the facts. ‘Discounter’ Tesco was only cheapest in one category: household goods, with an average price of £2.32 against nearest rival Asda’s £2.44. Waitrose’s oft-repeated assurance that its branded products are competitive on price with Sainsbury’s also takes a knock.

Without exception, Waitrose is the most expensive retailer in every category examined. It managed to narrow the price gap on branded to £2.39 against an average of £2.32, but still lagged behind the big four. On own label, Waitrose came in at £2.49, 43p higher than the average.

The cheapest retailer for branded goods was Asda. On own label, though, Morrisons took first place and was on average 3p cheaper than Asda.