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.
Social Fund (UK)
The Social Fund (UK) should not be confused with social funds in developing countries (sometimes also called Social Investment Fund, Social Fund for Development, Social Action Fund, National Solidarity Fund or Social Development Agency), or with the European Social Fund.