The price of groceries has increased at its fastest rate for 13 years, according to new figures.

Researchers at Kantar revealed that grocery price inflation reached 7% over the past four weeks to mark the highest level since May 2009.

Dog food, savoury snacks and fresh meat saw particularly sharp price rises, although spirit prices slipped for the month.

Fraser McKevitt, head of retail and consumer insight at Kantar, said: “People are really feeling the squeeze at the supermarket tills and they’re having to stretch their budgets further to accommodate rising prices.

“To put the most recent numbers into context, if you were picking up supplies for a family fry-up over the long weekend with toast, eggs, sausages, bacon and beans it would cost you £6.83 – that’s a significant 40p increase on last year.”

Kantar added that its recent survey found that 22% of households are “struggling” to make ends meet, with the rising price of the weekly shop a concern for more than nine in 10 of these people.

The latest figures also reported that supermarket sales dropped by 4.4% over the 12 weeks to May 15.

It reflected a softer decline than previous periods, with sales over the last four weeks only down 1.7%.

The research firm said it represented the strongest month since Christmas.

Mr McKevitt said there are already signs that UK households are spending money ahead of the Platinum Jubilee weekend.

He said: “With a four-day bank holiday weekend on the horizon, we’re expecting people to celebrate with friends and family.

“Looking back at the Diamond Jubilee in 2012, we saw a 10% boost in supermarket sales during the week leading up to the festivities.

“We should never underestimate the appetite for a party, especially a royal one.

“Summer refreshments back then were top of the shopping list and both alcohol and soft drink sales shot up.”

Lidl and Aldi were the strongest performing retailers for the period as shoppers turned to the discounters amid pressure on their finances.

Lidl sales increased by 6.0% in the 12 weeks to May 15, marginally ahead of Aldi which increased sales by 5.8%.

Despite reporting a fall in sales, Tesco also performed strongly as it grew its market share following a smaller decline than key rivals Sainsbury’s, Asda and Morrisons.