The UK Cost of Living series is built from official UK price and economic statistics published by the Office for National Statistics, and updated as each release lands.
Office for National Statistics (ONS)
Produces Consumer price indices (CPIH, CPI and core CPI), the Retail Prices Index, producer input and output prices, average weekly earnings, and the national-accounts trade figures behind the implied import deflator · Monthly for prices and earnings; quarterly for the trade figures used in the import deflator
The ONS collects around 180,000 prices a month from shops and online for the consumer indices, with basket weights drawn from the Living Costs and Food Survey. Producer prices and average weekly earnings come from business surveys of UK firms and employers.
The cost of imports is shown as an implied deflator (imports at current prices divided by imports at chained-volume prices), not an official ONS index, and the repair composite in Episode 5 is an Encyclix-derived blend of construction-materials and transport costs with no single official source.
United Kingdom