Summary
UK HPI and Price Paid Data both come from official housing market evidence, but they answer different questions. UK HPI is best for understanding broad market trends and time adjustment. Price Paid Data is best for checking individual completed sales in England and Wales.
Definition
The UK House Price Index, or UK HPI, tracks changes in residential property values using completed transaction data across the UK. It is useful when you need trend, local authority level price movement, property type context or a time adjustment between sale dates. HM Land Registry Price Paid Data records individual residential property sales in England and Wales that are sold for value and lodged for registration. It is useful when you need nearby comparable sales, but it should be filtered carefully for property type, tenure, new build status, date and weak evidence. For area checks, use UK HPI for the trend and Price Paid Data for very local evidence.