”The price of food, fuel, fertiliser and labour have all gone up. We are seeing substantial cost impacts and they are not going to go away tomorrow.

”Households up and down the country are facing real challenges. It is challenging for customers and challenging for households trying to manage their budgets.”

His warning came as Sainsbury’s intensified a price-cutting spree. The grocer said it is ploughing £500m into slashing the cost of essential items including milk, eggs, meat, fish, fruit and vegetables.

Roberts said: “Customers are watching everything they are spending. We have to work hard to make sure we hold back as much of the impact from customers as possible.”

His comments came a week after former Marks & Spencer boss Steve Rowe warned that shoppers will rein in spending this autumn in response to the cost of living crisis.

Other major grocers have pledged to focus on keeping the weekly shop affordable for families grappling with spiralling inflation and energy bills.

Asda has ploughed £90m into expanding its Just Essentials range and placing a price lock on more than 100 of its bestselling items for the remainder of the year.

Tesco has added 100 products in the past month to its Low Everyday Prices range while expanding its Aldi price match to compete with the German discounter.

Kantar said last week that grocery prices were rising at their fastest rate for 13 years, jumping 7 per cent in the past year.