NS&I Index-linked Savings Certificates are also known as inflation-beating savings and are designed to give savers a guaranteed tax-free rate of return, higher than the rate of inflation measured by the Retail Prices Index (RPI), if held for the full certificate term.
The certificates were launched in 1975 and were initially available exclusively to pensioners as a way of protecting their savings against high inflation. In 1981 the exclusivity of the certificates was dropped and they were made available to all savers.