UK Inflation Jumps to 3.5% as Pump Prices Climb

Analysis

Consumer prices rose 3.5% in the year to September, up from 3.1% in August, the Office for National Statistics said on October 21. Transport, mainly motor fuels, made the largest upward contribution. Core inflation also rose, two weeks before the Bank of England's next rate decision.

The Office for National Statistics (ONS), the UK's official statistics body, published the figures in its September 2026 consumer price inflation bulletin . The Consumer Prices Index (CPI) tracks the price of a fixed basket of goods and services that households buy.

What the numbers show

Headline. CPI rose 3.5% in the 12 months to September, up from 3.1% in August. Prices rose 0.4% in September alone, compared with little change in September 2025.

Core. Core CPI, which leaves out energy, food, alcohol and tobacco, rose 2.8%, up from 2.6%.

Goods and services. Goods inflation rose from 2.7% to 3.2%. Services inflation rose from 3.4% to 3.7%.

The driver. Transport was the largest contributor to the annual rate, at 0.94 percentage points, and motor fuels made the largest upward contribution to the change. Motor fuel prices were 29.8% higher than a year earlier, against a 23.0% annual rise in August.

At the pump. Petrol averaged 169.5 pence per litre in September, the highest since August 2022. Diesel averaged 192.5 pence per litre, the highest since July 2022.

Offsets. Restaurants and hotels made the largest downward contribution. Food and non-alcoholic drink inflation held at 1.3%.

Neighbours. The ONS put UK CPI above France (3.4%) and Germany (3.3%) for September, on a comparable measure.

The government's own pump survey points the same way. The Department for Energy Security and Net Zero's weekly road fuel prices ( data file , edition of October 13) show diesel averaging 200.04 pence per litre in the week of October 12, up from 186.36 pence in the week of September 7. That October reading comes after the September period the ONS measured, so it is not in this CPI figure.

How a fuel price becomes an inflation number

Start at the pump. CPI is a weighted average: each item's price change counts in proportion to how much households spend on it. A large rise in something people buy every week, such as petrol, moves the total even if most other prices are calm.

Fuel then travels further. Diesel powers the lorries that move food and goods, so a higher diesel price is a cost for shops and hauliers that can reach shelf prices later. That is why economists watch core inflation, the measure that strips out energy and food. Core rising too in September (2.8%, from 2.6%) means the pressure is not only at the pump, though one month does not show that fuel caused it.

The ONS bulletin measures the price changes but does not identify a single cause for the rise in fuel prices.

Worth knowing: the 2% target that the Bank of England aims at has applied to CPI only since December 2003. Before that the target was 2½% for RPIX, a measure based on the older Retail Prices Index, according to the Treasury remit annex setting out the change. The switch is why September's 3.5% is judged against 2%.

The causal chain

Motor fuel prices rose 29.8% over the year, making transport the largest contributor to 3.5% headline CPI; core inflation was 2.8%.

Conditional steps (not yet observed):

Rates. At its September meeting the Bank of England's Monetary Policy Committee (MPC) held Bank Rate, its main interest rate, at 3.75% by a 6–3 vote, with three members voting to raise it to 4%, according to its September summary . It said then that inflation was likely to rise further over coming quarters. If the committee reads September's core and services rise as persistent, the case for those votes could gain support at its November 5 decision .

Households and firms. If diesel stays above 200 pence, haulage and delivery costs could pass into goods prices over the coming months.

Markets. Higher expected UK rates could, in principle, affect gilt yields (the yields on UK government bonds) and the pound. This article measures no market reaction.

What is not justified: one month of data does not show a lasting inflation trend, and the bulletin does not attribute the fuel rise to any single event. Nothing here says how the November vote will go.

Counter-case

Fuel can fall as fast as it rose. If crude and diesel prices ease, the motor-fuel contribution would shrink quickly, and a one-off jump in pump prices drops out of the annual comparison after twelve months. Food inflation, at 1.3%, remains low, and restaurants and hotels pulled the rate down.

What the evidence does not show

How much of the rise in core and services inflation is linked to fuel.

Whether the October pump-price rise will carry into October's CPI, due on November 18.

How the MPC will vote on November 5.

What we're watching

The October CPI release on November 18, and whether core keeps rising.

The weekly government fuel survey, especially diesel against the 200-pence mark.

The November 5 MPC vote split and its Monetary Policy Report.

What would change our view

A fall in pump prices in the weekly survey, with core inflation steady or lower in October, would point to a temporary fuel spike. A further rise in services inflation would point to broader pressure.

Sources

Consumer price inflation, UK: September 2026 , Office for National Statistics, October 21, 2026.

Weekly road fuel prices , Department for Energy Security and Net Zero, updated October 20, 2026; data file , edition of October 13, 2026.

Monetary Policy Summary, September 2026 , Bank of England, September 17, 2026.

Upcoming MPC dates , Bank of England.

Remit annex on the new inflation target , HM Treasury, December 2003, hosted by the Bank of England.