I don’t trust any graph without at least its axes and captions, so here’s the source.

https://www.ons.gov.uk/economy/inflationandpriceindices/bulletins/consumerpriceinflation/april2024

While I think the message here is important, this particular plot seems to be of “Owner Occupier’s Housing Costs” and this capture conveniently crops the frame so that you don’t see the dip just before 2019.