FILE PHOTO: Fuel pumps are seen at a Texaco petrol station in London, Britain, July 26, 2017. REUTERS/Hannah McKay

LONDON (Reuters) - Britain’s statistics agency said it had miscalculated April inflation data published on Wednesday, understating the true rate of price growth, after using incorrect petrol and diesel prices.

April’s Retail Prices Index measure of inflation should have been 3.1% rather than 3.0%, the Office for National Statistics said on Friday.

“In line with the published revisions policy for consumer price inflation statistics, this error will not be corrected in the published RPI series,” the ONS said.

Unlike most other British economic data, published inflation figures are not generally open to revision even in clear cases of error, according to the ONS’s policies.

The RPI measure is not Britain’s headline rate of inflation but is used for indexing British inflation-linked bonds as well as historic employer-provided pensions, rail fares and other commercial contracts.