The pace of UK price rises accelerated ahead of Chancellor John Healey's first Budget, pushed up by sharp increases in petrol and diesel prices.
The rate of inflation rose to 3.5% from 3.1% in the year to September, according to the Office for National Statistics (ONS).
The cost of filling up a vehicle has soared in recent months as conflicts in the Middle East and Europe continued to squeeze global oil supplies.
Petrol prices in September were the highest since August 2022, the ONS said, while diesel also rocketed.
The average price of petrol rose by 8.2p per litre to 169.5p per litre between August and September, while diesel rose to 192.5p per litre.