The ONS version is at 8.7%, calculated monthly, but that includes such things a flying, going to live music venues / theatres, eating out at proper restaurants and buying second-hand cars. I bet that the majority of us do not do many of those things regularly on a monthly basis.
It also includes the 20% ish inflation often quoted for food prices. This is also a fix. The basket of goods, although allowing for some fresh fruit, veg and meat, concentrates on "brands", ready meals, pies, cereals and other top-of-the-range items as well as crisps. pop, cakes and other non-essentials. It also quotes the energy price cap making out that it is "normal" or "average". The current price cap is £3,280 and that allows a household to spend £36 per day on energy - April, May, June. Normal or an average my fundament.
My personal inflation sits as about 4.2% but that includes the winter fuel payments. Without it it would be 6.7%.
The problem with the media throwing out these numbers is that commercial interests use them as a benchmark - "oh look, our prices are below inflation".