UK Inflation Rises to 3.5% in September Driven by Fuel Price Surge

The UK inflation rate increased to 3.5% in the year to September, up from 3.1%, marking the fastest rise since October 2025. This acceleration was mainly driven by sharp increases in petrol and diesel prices, with motor fuel prices overall rising by 29.8% over the period, according to the Office for National Statistics (ONS).

Petrol prices rose by 8.2p per litre to 169.5p, and diesel prices reached 192.5p per litre by September. These increases are linked to global supply disruptions caused by conflicts in the Middle East and Europe, including disruptions at the Strait of Hormuz and damage to oil refining infrastructure in Ukraine and Russia. Other factors contributing to inflation included rising costs for airfares, computer games, and live events.

The inflation data preceded Chancellor John Healey's first Budget. Government borrowing in September rose to nearly £25 billion, £1.8 billion higher than the previous year, driven by higher debt interest costs amid inflation. The Chancellor aims to adhere to fiscal discipline and promote growth while managing inflationary pressures. Economists suggest the upcoming Budget will likely be cautious with limited immediate economic impact but may defer difficult fiscal decisions until next year.

This inflation increase and government borrowing escalation matter for investors because they affect the UK’s economic outlook and fiscal policy decisions. Rising inflation and borrowing costs can influence interest rates, government spending, and overall market conditions. The £25 billion borrowing figure highlights fiscal pressure that could shape the Budget and future economic policy.