The ONS says that it plans to introduce "improved data and methods" for groceries in their consumer price inflation (CPI) statistics. And that this will take effect from February 2026. So, just be wary of that.
The impact of the change is minimal but not entirely inconsequential with the UK stats office noting that past changes showed a negative 0.03% change to the CPI estimate.
As much as this might be an "improvement", the ONS has bigger fish to fry. They're still facing plenty of backlash and scrutiny over the lack of accuracy and credibility in delivering the labour market report for quite some time now. And that's an issue that looks like it will drag on further. From before: UK statistics office evaluates potential delay to its overhauled jobs survey - report
