Consumer price indices (CPI) are important indicators of how the UK economy is performing.
The indices are used in many ways by the government, businesses, and society in general. They can affect interest rates, tax allowances, wages, state benefits, pensions, maintenance, contracts and many other payments. They also show the impact of inflation on family budgets and affect the value of the pound in your pocket.
A complete introduction can be downloaded from Consumer Prices Index: A Brief Guide (319.6 Kb Pdf)