Did inflation drop last month? Well, it’s complicated…

New data published today by the Office for National Statistics (ONS) shows that inflation stood at 3.4% in the 12 months to May 2025.

But different media outlets have reported this figure in different ways—BBC News and the MailOnline said inflation has “held” at 3.4%, while Sky News said “inflation falls slightly” and the Guardian referred to a “fall” on the previous month’s figures.

The confusion is due to an error with April’s inflation figures. Last month, the ONS initially reported that the Consumer Prices Index (CPI) had risen from 2.6% in the 12 months to March 2025 to 3.5% in the 12 months to April 2025.

However earlier this month it revealed that incorrect road tax data provided by the Department for Transport had had “the effect of overstating” April’s figure by 0.1 percentage point.

In other words, the true CPI figure for the 12 months to April 2025 should have been 3.4%, which would mean that the figure published today for May is unchanged on the previous month, not a fall.

So why have some media outlets nonetheless reported today’s figure as a drop? Well, despite the ONS acknowledging this mistake, the figures on its website won’t be updated. So the official figure for inflation in the year to April remains 3.5%, as noted in the ONS’ data release today, even though it’s known to be an overestimate and based on incorrect data.

When we asked the ONS about this this morning, it told us that its policy was that CPI figures “may only be revised in exceptional circumstances”, adding: “We have incorporated the correctly weighted data from today’s May figures, meaning no further statistics will be affected.”

As a result, you might see a few conflicting headlines today.