The largest upward contribution to the change came from transport services, notably air fares with the timing of Easter in April a likely factor in the movement. There were also significant upward effects from food and motor fuels.
The largest offsetting downward effect came from recreation and culture, particularly games, toys and hobbies (such as computer games) and data processing equipment.
CPIH (not a National Statistic) grew by 0.4% in the year to May 2015, up from 0.2% in April.
David Lamb, head of dealing at forex specialists FEXCO, commented:
"April's brief spell of deflation is likely to be a footnote rather than a fundamental trend.
"The freefalling oil price which precipitated the slide into deflation is over, wages are rising and business confidence is up. Together this has nudged the CPI back into positive territory - its first rise since October.
"While 0.1% inflation is still a long way short of the Bank of England's target, the end of deflation means the Bank is likely to leave the monetary policy panic button well alone.
"The chances of an interest rate cut were always slim, but they have now all but vanished.
"But such anaemic levels of price growth are hardly inspiring - and despite the excitement in some parts of the market, Sterling has been left listless."
