The inflation target of 2% is expressed in terms of an annual rate of inflation based on the Consumer Prices Index (CPI). The remit is not to achieve the lowest possible inflation rate. Inflation below the target of 2% is judged to be just as bad as inflation above the target. The inflation target is therefore symmetrical.
If the target is missed by more than 1 percentage point on either side – i.e. if the annual rate of CPI inflation is more than 3% or less than 1% – the Governor of the Bank must write an open letter to the Chancellor explaining the reasons why inflation has increased or fallen to such an extent and what the Bank proposes to do to ensure inflation comes back to the target.
A target of 2% does not mean that inflation will be held at this rate constantly. That would be neither possible nor desirable. Interest rates would be changing all the time, and by large amounts, causing unnecessary uncertainty and volatility in the economy. Even then it would not be possible to keep inflation at 2% in each and every month. Instead, the MPC’s aim is to set interest rates so that inflation can be brought back to target within a reasonable time period without creating undue instability in the economy.