HICPs are calculated in each Member State of the European Union, according to rules specified in a series of European Regulations developed by the EU statistical office in conjunction with the EU Member States. In the UK, the HICP is known as the CPI, but the two remain one and the same index.
The consumer prices index (CPI) is the main United Kingdom domestic measure of inflation for macroeconomic purposes. The uses of the retail prices index (RPI) include indexation of pensions, state benefits and index-linked gilts. Both measure the average change from month to month in the prices of consumer goods and services purchased in the UK, although there are differences in coverage and methodology.
Both the CPI and the RPI are compiled each month using the same underlying price data, based on a large and representative selection of around 650 individual goods and services for which price movements are measured in around 150 areas throughout the UK.