It’s been another gloomy week for retail. And the latest figures from The Grocer Price Index are likely to bring equal misery for consumers, with the price of groceries continuing to rise sharply.

Grocery prices across the UK’s big four supermarket groups were up 5% on the same period last year, according to figures compiled for The Grocer by, which monitors prices of both branded and own-label products across all major grocery categories.

The retailers are acutely aware of the difficulties shoppers are facing in terms of managing budgets, and are continuing to advertise big promotions and money-saving ideas but even with promotions factored in, customers are still paying 4% more for their shopping than a year ago.

As The Grocer revealed last week, all of the major multiples with the exception of Sainsbury’s increased the number of deals they were offering during June, compared with the previous month.

But with sales across the sector virtually flat, retailers are starting to feel the squeeze as much as their customers and are seriously concerned about exactly how much they can continue to sell on ­promotion.

As such, over the coming months we could see a lessening of the mitigating impact of promotions on inflation, which would create bigger headaches for consumers. There is also likely to be an increase in tension between retailers and suppliers as the mults look to try and keep a lid on price rises.

The picture without looking at the impact of promotions was broadly the same this month. Asda, Morrisons and Sainsbury’s were all on average 5% more expensive than this time last year, while Tesco’s prices were 6% higher.

However, big differences start to appear when offers are factored into the equation. Asda shoppers are only paying 2% more at the till than they were a year ago, and Morrisons’ shoppers 3%. Sainsbury’s prices were 5% dearer, suggesting it was offering broadly the same level of deals as a year ago, while Tesco’s prices were up 8%, suggesting it was offering its shoppers significantly more ­discounts last year than it is now.