UK inflation stayed stuck at 8.7% in May as prices for recreation and cultural activities rose at a faster pace than the previous month.

The data released by the Office for National Statistics Wednesday defied forecasts for a slowdown in overall inflation to 8.4% compared with a year ago. Although the prices of groceries rose less sharply than in April, food inflation remained high, coming in at more than 18%.

"The cost of airfares rose by more than a year ago and is at a higher level than usual for May," said ONS chief economist Grant Fitzner. "Rising prices for second-hand cars, live music events and computer games also contributed to inflation remaining high."

The shock is bad news politically for UK Prime Minister Rishi Sunak, who has promised to halve the rate of inflation this year, and economically for millions of people across Britain struggling with a cost-of-living crisis and facing soaring mortgage payments, with interest rates on two-year loans now above 6%.

Before May, inflation had fallen for two consecutive months.

The latest figures make it more likely the Bank of England will raise interest rates again Thursday, threatening even more turmoil in the mortgage market.

— This is a developing story and will be updated.