An increase in the general level of prices that persists over a period of time. The inflation rate is a measure of the average change over a period, usually 12 months. If inflation is up 4%, this means the price of products and services is 4% higher than a year earlier, requiring we spend and extra 4% to buy the same things we bought 12 months ago and that any savings and investments must generate 4% (after any taxes) to keep pace with inflation. Since 2003, the Bank of England has used the consumer prices index (CPI) as its official measure of inflation (see also retail prices index).
The Consumer Price Index is the official measure of inflation adopted by the government to set its target. When commentators refer to changes in inflation, they’re actually referring to the CPI. In the June 2010 Budget, Chancellor announced the government’s intention to also use the CPI for the price indexation of benefits, tax credits and public sector pensions from April 2011. (See also Retail Prices Index).