Morrisons has claimed the title of the UK's cheapest supermarket basket, outperforming rivals Tesco, Asda and Sainsbury's, thanks to an aggressive round of promotions and discounts. In the final mystery shop of the Grocer 33 year, an industry benchmark for grocery price comparison, Morrisons delivered the lowest overall basket cost at £72.39.

The total included eight deep promotions on key branded items such as Birds Eye chicken pies and This plant-based sausages. These discounts, part of a wider set of 16 promotions, helped the retailer slash 9.8% off its base prices.

Morrisons' win marks a notable shift in the supermarket price wars, as it often lags behind Asda and Tesco in cost-competitiveness, the Grocer reported.

However, with a blend of multibuy offers and price reductions, it led the pack this time.

Close on Morrisons' heels was Asda, with a basket total of £72.69, just 30p more.

Asda had more exclusively cheapest items than any other retailer, with 13 of its products topping the affordability chart. These included an Absolut & Sprite RTD can, dauphinoise potatoes and Kellogg's Coco Pops cereal bars.

However, when adjusted to reflect multibuy savings, Morrisons held a 6.4% lead over Asda, underlining the value of its strategic promotional pricing.

Sainsbury's came in third with a basket total of £75.96, 4.7% more expensive than Morrisons.

It offered the best prices on muffins and Muller Rice but lacked the volume of deals seen at its competitors.

Tesco followed closely with a basket cost of £76.66. The supermarket's Clubcard Prices helped bring down the cost of certain items, such as the Schar gluten-free loaf and Oreo Ice Cream Mini Sandwiches, but it still trailed behind on overall value.

Waitrose, unsurprisingly, had the most expensive basket at £82.79, though it did offer the best price on Alpro coconut drink and Marigold gloves.

According to the latest ONS data, chocolate prices have surged by a record 17.7% in the year to May, with Cadbury's drinking chocolate up 14%, one of the steepest hikes in the basket. This sausages saw a similarly sharp increase.

Despite that, 17 products in the Grocer 33 basket were actually cheaper than this time last year. Dauphinoise potatoes dropped by 13%, while Nivea moisturiser fell 11%, offering consumers some relief amid the wider cost-of-living squeeze.