Inflation is when prices rise. Deflation is the opposite – price decreases over time – but inflation is far more common.

If inflation is 10%, then a £50 pair of shoes will cost £55 in a year's time and £60.50 a year after that.

Inflation eats away at the value of wages and savings – if you earn 10% on your savings but inflation is 10%, the real rate of interest on your pot is actually 0%.

A relatively new phenomenon, inflation has become a real worry for governments since the 1960s.

As a rule of thumb, times of high inflation are good for borrowers and bad for investors.

Mortgages are a good example of how borrowing can be advantageous – annual inflation of 10% over seven years halves the real value of a mortgage.

On the other hand, pensioners, who depend on a fixed income, watch the value of their assets erode.

The government's preferred measure of inflation, and the one the Bank of England takes into account when setting interest rates, is the consumer price index (CPI).

The retail prices index (RPI) is often used in wage negotiations.