Although unchanged overall, there were significant changes between the upward and downward pressures between April and May.
According to the ONS, the largest downward pressure to the change in CPI inflation came from transport services. The timing in Easter in 2011 had a significant impact on the April figures for air, sea and international rail travel since it fell in the collection period.
Another large downward pressure came from furniture, household equipment and maintenance where prices, overall rose by 0.4% between April and May this year compared to a rise of 1.2% a year ago.
The largest offsetting upward pressure to the change in CPI inflation came from food and non-alcoholic beverages where prices, overall, rose by 1.3% between April and May this year but fell by 0.1% between the same two months a year ago.
Large upward pressures also came from alcohol & tobacco as well as miscellaneous goods & services.
In the year to May, RPI annual inflation was 5.2%, unchanged from April. The main factors affecting the CPI also affected the RPI.
