The maximum investment is £15,000 per issue per individual. The 3 year (20th issue) and 5 year (47th issue) certificates are both currently paying 1% p.a. plus RPI. If we assumed that RPI was currently around 4% p.a., that gives a return of 5% p.a. Importantly, this is tax free. For a 50% taxpayer this therefore represents a gross equivalent return of 10% p.a. For a 40% taxpayer it is 8.33% p.a. and 6.25% p.a. for a 20% taxpayer. RPI is compiled and published monthly by the Office for National Statistics (ONS).

Naturally, because inflation fluctuates, you won’t know exactly how much you will receive until your certificates mature. You should note that no index-linking or interest will be earned on certificates cashed in within one year of purchase. Other terms and conditions apply where certificates are cashed in prior to maturity.

NS&I is one of the largest savings organisations in the UK, with almost 27 million customers and over £94 billion invested. They are best known for Premium Bonds but also offer a range of other savings and investments to suit different people’s needs. Importantly, all products offer very high levels of security, because NS&I is backed by HM Treasury.