The measure of UK inflation turned negative in April for the first time, with the rate falling to -0.1%.
It is the first time Consumer Price Index (CPI) inflation has turned negative since 1960, based on comparable historic estimates, the Office for National Statistics said.
The biggest contribution to the fall came from a drop in air and sea fares reported BBC.
Bank of England governor Mark Carney said he expected inflation to remain very low over the next few months.
But Mr Carney added that “over the course of the year, as we get towards the end, inflation should start to pick up towards our 2% target”.
The latest inflation figures show that transport costs were 2.8% lower in April than the same time a year ago, while food was 3.0% cheaper.
Chancellor George Osborne said the inflation figure should not be mistaken for “damaging deflation”.
He added that the lower cost of living – driven by last year’s fall in oil prices – would be a welcome relief for family budgets, in an environment in which average wages were finally beginning to rise.