National Insurance number
The National Insurance number is used as a reference number in the Pay As You Earn system, and also by the self-employed. It is also used in applications for Individual Savings Accounts (ISAs), to check that an individual has opened only one ISA in a tax year.
State Earnings-Related Pension Scheme
The State Earnings Related Pension Scheme (SERPS), originally known as the State Earnings Related Pension Supplement, was a UK Government pension arrangement, to which employees and employers contributed between 6 April 1978 and 5 April 2002, when it was replaced by the State Second Pension.