https://image.nostr.build/8e5b13b1d63c6bfacbb1bd18ea1e3b15cf4e1b170f46899701db5e88d235289c.png

RHS: Consumer Price Index (CPI) in the United Kingdom from 1st quarter 1988 to 1st quarter 2024
LHS: Retail Price Index (RPI) in the United Kingdom from 1st quarter 1987 to 1st quarter 2024

“We have been clear that the RPI is not a good measure, at times significantly overestimating inflation and at other times underestimating it and have consistently urged all – in Government and the private sector – to stop using it." Chair of the UK Statistics Authority, 2019

*Still* the RPI used to set most excise duty rates and the amount of interest charged on student loans.