Britain’s main measure of wage growth may need to be revised after a large employer failed to supply earnings data on time, the troubled Office for National Statistics has warned.

In the latest sign of the ONS’s problems with collecting reliable economic figures, which the government uses in economic policymaking, the agency issued a caveat alongside March’s average weekly earnings data that “as an exception” it was working on “opening up revisions further back in time” for the figures.

“This will allow for late and updated returns we received from one business to be included, as part of improving the quality of these estimates,” it added.

The ONS conceded that such revisions to the figures from one unnamed employer “may have a small impact at a whole-economy level”. The data agency vowed to provide a “full explanation” when it published the revisions.

The admission from the statistics agency, first reported by the Financial Times, is the latest acknowledgment of problems with a range of key economic statistics in the past few months, which are relied on by ministers, the Bank of England and the Office for Budget Responsibility (OBR).

It emerges hours before the chancellor, Rachel Reeves, makes her spring statement address to the Commons in response to the OBR’s latest forecasts, when she is expected to announce further cuts to welfare to balance the books.

A separate report on Wednesday outlined concerns about the reliability of another key ONS survey, in this case local employment levels. Researchers cautioned that the data was “volatile” and had significant flaws and limitations, the FT reported.

This comes after the ONS said there were errors in the growth figures it used to calculate the size of Britain’s economy, resulting from problems with its “factory gate prices” data.

At the same time, the statistics agency is battling to fix problems with the crucial labour force survey, which provides headline unemployment and employment data. The ONS has had to spend millions on temporary workers to fix the survey, which has been described as “virtually unusable”.

Experts have said the string of problems with ONS figures have meant the Bank of England, OBR and the government are “flying blind”, given concerns about the reliability of economic data after months of sustained pressure on the agency.

The ONS has said it could take until 2027 to rectify the problems with its labour market survey, which as the official measure of employment in the UK is crucial for policymakers and ministers.

The Bank of England governor, Andrew Bailey, was so concerned about the jobs survey that he raised it as a “substantial problem” at the annual Mansion House event in the City in late 2024.

The ONS also said, earlier in the month, that it could not reverse a pandemic-era decision to release official data on the state of the economy before financial markets opened because its creaking website could crash.