Inflation in Britain is forecast to be the highest among all advanced economies in 2025 and 2026, according to new predictions by the International Monetary Fund (IMF), in a pre-Budget blow to chancellor Rachel Reeves.

Price growth in the UK is now predicted to have averaged 3.4% in 2025, up 20 basis points from the IMF’s July prediction of 3.2%, making it the highest among all advanced economies, says the World Economic Outlook report.

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The IMF says the rise in headline inflation in the UK in 2025 is partly due to the changes in regulated prices (those controlled by the government), many of which increased in ‘Awful April’.

The pain is set to continue into next year too as inflation is expected to average 2.5% in 2026, another 20 basis points higher than the IMF’s previous prediction (2.3%).

Thankfully, inflation is expected to fall much closer back towards the Bank of England’s 2% target by the end of 2026, which the IMF says will be helped by “a loosening labour market and moderating wage growth”.

The IMF’s prediction of inflation falling in 2026 is one shared by most inflation forecasters, including the Bank of England.

United States.

However, economic growth forecasts have been downgraded for 2026 as UK GDP growth is expected to remain at 1.3%, down from the 1.4% predicted in July.

Chancellor Rachel Reeves welcomed the upwards growth revision for 2025, saying: “This is the second consecutive upgrade to this year’s growth forecast from the IMF. It’s no surprise, Britain led the G7 in growth in the first half of this year, and average disposable income is up £800 since the election.

“But know this is just the start. For too many people, our economy feels stuck. Working people feel it every day, experts talk about it, and I am going to deal with it. Working together, we can deliver a Britain built for all.”