Consumer inflation in the UK fell by more than analysts had predicted as the falling price of fuel, food and cheaper consumer goods all had an impact.
The Consumer Prices Index fell from 5.2% in September to 4.5% in October; the biggest monthly fall in 16 years, figures from the Office for National Statistics revealed.
Many analysts had expected inflation to fall to around 4.8% but the drop should pave the way for further interest rate cuts to boost the economy.
The Retail Prices Index - which also includes housing costs - also fell, from 5% to 4.2%.
The Bank of England has said inflation could fall to 1% next year, below its target rate of 2%, which would raise the possibility of deflation.