Shoppers have witnessed their grocery bills surge at the fastest rate since 2008 following spikes in the price of butter, milk and chicken, according to new data.

Research firm Kantar has revealed grocery price inflation jumped to 11.6% for the four weeks to August 7, compared with 9.9% in the previous month.

It said this equates to a £533 annual increase in the average UK household’s grocery bill.

As a result, it reported sales of own-label value products increased by almost a fifth – 19.7% – as shoppers sought to make savings.

Fraser McKevitt, head of retail and consumer insight at Kantar, said: “As predicted, we’ve now hit a new peak in grocery price inflation, with products like butter, milk and poultry in particular seeing some of the biggest jumps.

“This rise means that the average annual shop is set to increase by a staggering £533, or £10.25 every week, if consumers buy the same products as they did last year.

“It’s not surprising that we’re seeing shoppers make lifestyle changes to deal with the extra demands on their household budgets.”

It came as overall supermarket sales rose by 2.2% in the 12 weeks to August 7.

Experts said that consumers are now shopping around more and switching supermarkets in response to the cost-of-living crunch.

Lidl was once again the fastest growing supermarket chain, with sales up by 17.9% over the latest 12 weeks.

Rival German discounter Aldi also performed strongly, reporting 14.4% growth, as customers were attracted to the two firms’ cheaper product lines.

Tesco was the strongest performer among the UK’s biggest grocers, reporting 1% growth.

Meanwhile, Asda saw sales increase by 0.2% and Sainsbury’s recorded a 0.1% dip.

The worst performer of the big four was Morrisons, which saw sales decline by 4.9%.

Recent hot weather also resulted in a surge in sales of soft drinks, ice cream and summer clothes, according to the report.

Mr McKevitt added: “As the mercury climbs, shoppers have turned to mineral water and soft drinks to cool off.

“Sales of both products are up by 23% and 10% respectively in the latest four weeks.

“Unsurprisingly, ice creams are also popular with 18% year on year growth, up by four percentage points on the previous month.”