Consumer prices rose by 3.2 per cent in the year to March, down from 3.4 per cent in February, the Office for National Statistics said.
That is the lowest level since September 2021.
The fall in the annual rate was not as big as anticipated, with economists predicting 3.1 per cent for the month.
Inflation is still running higher than the Bank of England's target of two per cent but the direction of the move appears clear.
Inflation hit a high above 11 per cent at the end of 2022 following Russia's invasion of Ukraine, which led to sharp increases in energy costs.
The fall means the UK's inflation rate is lower than the US's for the first time in two years.
In March, inflation in the US rose to 3.5 per cent.
Inflation is set to fall further in April, possibly to below two per cent as a result of sharply lower domestic energy bills, which economists think could prompt rate-setters at the Bank of England to consider a cut in interest rates in the next few months from the 16-year high of 5.25 per cent.
However, a number of the nine policymakers have warned the fight against inflation is not over yet as they expect prices to start rising again in the second half of the year.
The Bank of England, like the US Fed and other central banks around the world, raised interest rates aggressively in late 2021 from near zero to counter price rises first stoked by supply chain issues during the coronavirus pandemic and then by Russia's invasion of Ukraine.
Higher interest rates - which cool the economy by making it more expensive to borrow, thereby bearing down on spending - have contributed to bringing down inflation worldwide.
Britain's governing Conservative Party hopes that lower inflation and falling interest rates might trigger a feel-good factor leading up to a general election that has to take place by January 2025.
Opinion polls show the opposition Labour Party headed for a big victory over the Conservatives, who have been in power since 2010.
