The UK's statistics agency has said the headline inflation rate for April was too high after it discovered it had been given incorrect road tax data by the Department for Transport.
The Office for National Statistics (ONS) said the pace of general price rises should have been 3.4%, instead of the 3.5% it had reported.
It comes as the ONS faces a crisis of confidence in its work after concerns about the quality of its data.
These concerns make it more difficult for the government and companies to make fully informed decisions about the UK economy.