A National Insurance number is a personal account number assigned to residents of Great Britain and Northern Ireland who are at least 16 years old and contributing National Insurance payments and taxes, explains Tax Guide for Students. Every person who works and intends to claim benefits in the United Kingdom needs to obtain a National Insurance number.
The U.K. government uses National Insurance numbers to keep track of the tax and National Insurance payments of residents, according to Tax Guide for Students. National Insurance numbers also serve as reference numbers when contacting government departments.
Each person receives a distinct National Insurance number that should never be used by anyone else, notes Tax Guide for Students. All National Insurance numbers consist of two letters in the beginning, six numbers in the middle and one final letter. The government issues these numbers to residents who are about to turn 16 years old. People from other countries who plan to work in the United Kingdom must apply for National Insurance numbers.
The Department for Work and Pensions, HM Revenue and Customs, employers, pension providers, and financial institutions require individuals to provide National Insurance numbers, reports Tax Guide for Students. Anyone who loses or forgets his National Insurance number should check payslips, tax returns and other official documents, or call the National Insurance Registrations Helpline. The HMRC requires the submission of a form to verify a lost National Insurance number.