Core Retail Price Index (RPI) inflation in the United Kingdom accelerated in September 2026, rising to 3.9% year-over-year from 3.3% in August, according to data updated on 21 October 2026. The figures are calculated on an annual basis, comparing each month’s change with the same month a year earlier.
The uptick in core RPI — which strips out some of the most volatile components to provide a cleaner view of underlying price pressures — marks a reversal from the slowdown seen in August. The previous reading of 3.3%, recorded in August 2026, had suggested a modest easing in core inflation, but September’s data indicates that underlying price growth remains resilient.
With the latest report showing a firmer pace of core price increases, market participants and policymakers will be watching upcoming data closely to assess whether this represents a temporary bump or the start of a renewed inflationary trend in the UK’s retail sector.
