Supermarket shoppers have been warned as the cost of butter soared across the country in the last month.

Butter has risen in price by as much as 21 per cent in supermarkets over the last month.

Branded butter has seen the highest average price increase, with Trewithen Salted Block Butter 250g rising in price by 20.8 per cent in Tesco, from £2.40 to £2.90.

The analysis, from The Grocer magazine, found that 37 out of 117 butters at the major UK supermarkets had risen in price in the five weeks up to November 13.

At Waitrose, all Things Butter Garlic & Herb Butter 125g is up 20 per cent, while Country Life British Salted 250g and Unsalted Butter 250g at Sainsbury’s are up 13 per cent.

Some own brand butter products have also rise, with Asda’s block butter up 6 per cent to £1.92, while a 250g own brand block of butter at Sainsbury’s, Tesco, Morrisons, Aldi and Lidl has also risen by 6 per cent to £1.89.

It is understood the price increase is a result of tight supplies of milk and cream due to adverse weather conditions.

The news comes a month after shoppers were warned that while food inflation had been coming down in recent months, it was still in a “vulnerable” position.

In October Food inflation eased to 1.9%, down from September’s 2.3%, particularly for meat, fish and tea as well as chocolate and sweets amid Halloween deals.

British Retail Consortium chief executive Helen Dickinson said: “Households will welcome the continued easing of price inflation, but this downward trajectory is vulnerable to ongoing geopolitical tensions, the impact of climate change on food supplies, and costs from planned and trailed Government regulation.

“Retail is already paying more than its fair share of taxes compared to other industries.

“The Chancellor using tomorrow’s Budget to introduce a Retail Rates Corrector, a 20% downwards adjustment, to the business rates bills of all retail properties will allow retailers to continue to offer the best possible prices to customers while also opening shops, protecting jobs and unlocking investment.”

Mike Watkins, head of retailer and business insight at NielsenIQ, said: “Inflation in the food supply chain continues to ease and this helped slow the upward pressure of shop price inflation in October, however other cost pressures remain.

“Consumers remain uncertain about when and where to spend and with Christmas promotions now kicking in, competition for discretionary spend will intensify in both food and non-food retailing.”