Official data out Wednesday showed the annual rate of increase in the consumer prices index dropped to 3.9% from October's 4.6%.
Transport - particularly motor fuels - was the biggest contributor to the fall.
The reading was well below all forecasts in a Reuters poll of economists.
Key measures watched closely by Britain's central bank, including core and services inflation, also dropped.
The numbers left investors betting on the Bank of England cutting interest rates next year, perhaps as soon as May.
British inflation is now closer to other rich nations and matches that of France.
But consumer prices have risen since 2020 by a fifth - more than any other Group of Seven advanced economy.
One leading analyst said Wednesday's numbers showed strong evidence disinflationary pressures are building in the UK.
A much smaller rise in food and drink prices than in November last year also helped - although those prices are still 27% higher than two years ago.
Finance minister Jeremy Hunt said the data showed inflation pressures were being removed from the economy.
While the opposition Labour Party said people were worse off after 13 years of Conservative government.
