UK consumer price inflation accelerated in September, with the annual rate rising to 3.5% from 3.1% in August. The broader Consumer Prices Index including owner occupiers’ housing costs (CPIH) increased to 3.6% from 3.3%. Both measures recorded a 0.4% monthly rise.
The figures show how different measures describe related but distinct baskets. CPI is the headline measure commonly used in comparisons and monetary policy. CPIH also includes an estimate of the costs faced by owner-occupier households in living in their homes. The annual CPIH rate was therefore 0.1 percentage point above CPI in September; the two figures should not be used interchangeably.
Motor fuels were the main upward pressure
Transport made the largest upward contribution to the change in both annual rates, particularly because of motor fuels. The contrast with a year earlier mattered: petrol and diesel prices rose between August and September this year, whereas they edged down over the same months in 2025. Such year-on-year comparisons mean the annual inflation rate reflects both current price movements and the comparison period.
Average petrol prices increased by 8.2 pence a litre between August and September, reaching 169.5p a litre. Diesel rose by 10.7p to 192.5p a litre. The annual rate for motor-fuel prices was 29.8%, compared with 23.0% in August. These are price-index movements and average pump prices, not a claim that every forecourt or household experienced the same change.
Transport prices overall rose by 6.6% over the year, up from 4.6% in August, even though the division’s prices fell 0.4% month on month. That monthly fall was smaller than the 2.3% decline recorded in September last year, which also contributed to the higher annual rate. Air fares fell 19.5% over the month, but by less than the 28.8% fall a year earlier; that comparison exerted an upward influence on the annual change.
Offsetting movements and underlying measures
Restaurants and hotels provided the largest downward offset to the change in both headline annual rates. Their prices still rose by 0.5% in September, but that was less than the 0.8% monthly increase a year earlier. An offset means this category restrained the acceleration relative to other movements; it does not mean prices in the category fell overall.
Measures excluding energy, food, alcohol and tobacco also moved higher. Core CPI rose to 2.8% over the year from 2.6%; core CPIH reached 3.1% from 2.9%. Services inflation under CPI increased to 3.7% from 3.4%, while goods inflation rose to 3.2% from 2.7%. These indicators can help distinguish broad price movements from volatile categories, but they do not remove the direct effect of higher fuel costs from household budgets.
The September data are a snapshot of prices collected during that month, not a forecast of what shoppers will pay next. The next inflation release will show whether the monthly fuel comparison persists and whether price pressures are spreading or easing elsewhere. One month’s increase alone does not establish a lasting trend.
What the figures do and do not say
Higher inflation means the measured price level is rising faster than a year earlier; it does not mean every price rose by 3.5%, nor that prices themselves are falling when inflation later slows. The rates also do not quantify the effect on any particular household, whose spending pattern may differ from the national basket.
The release records the largest contribution to the change in the annual rate, rather than attributing the whole increase to one cause. Fuel movements were the leading upward influence, while the smaller restaurant and hotel increase relative to last year acted in the opposite direction. Other categories also contributed. Keeping those distinctions clear is important when interpreting the shift from August.
