Inflation in the UK rose to 3.5% in the year to September, the highest rate in nearly a year and above the Bank of England's 2% target.
The rise was slightly higher than economists had predicted, driven by higher petrol and diesel prices.
Inflation is widely expected to rise again in the coming months.
Inflation is the increase in the price of something over time.
For example, if a bottle of milk costs £1 but is £1.05 a year later, then annual milk inflation is 5%.