Families worried about the soaring cost of grocery bills were given some respite this week. The early lifting of the Russian export ban on wheat looks set to ease pressure on that key commodity, while exclusive research for The Grocer revealed that food price inflation has slowed in the past month.

The latest figures from The Grocer Price Index, the comprehensive tracker of food prices compiled by BrandView.co.uk, show that the cost of food and drink across the big four has risen 4% over the past year. However, once the impact of promotions is factored in, shoppers are only paying 3% more.

Year-on-year, the picture is exactly the same as it was last month. Month-on-month, though, inflation was down marginally, at 0.5% for the five weeks to 31 May with promotions taken into account, compared with 0.7% in April.

Despite its long-running price war with Asda, Tesco’s prices have climbed the most in the past year. Our trolley of goods, which covers all the major food and drink categories and includes branded and own-label products, revealed that prices at Tesco were on average 5% higher last month than they were a year ago and 1.2% higher than in April. However, once deals were included the actual prices paid by shoppers were 4% up on last year and 0.8% higher than in April.

Morrisons’ prices were also up 5% year-on-year, although the retailer appeared to be offering deeper discounts as its prices were only 3% up on last year with promotions included. Because of this, it also posted the smallest increase in actual prices month-on-month, up just 0.3% on April.

Of the big four, Asda recorded the smallest rise in year-on-year prices, at just 3%. Promotions had no impact on its pricing, suggesting it is beginning to make good on its promise to become less dependent on deals and return to a clearer EDLP pricing strategy.

Sainsbury’s base price was 4% higher than a year ago and 3% higher after its deals were factored in, while customers at Waitrose, which is not included in the GPI, were only paying 2% more for their shopping this May compared with last.