People 16 and over who live or work in the United Kingdom need a National Insurance number in order to pay taxes, receive benefits and make contributions to their state pension. Once an individual has been issued with this personal tax number, it stays with him for life, even if he changes his name, nationality or marital status.
In order to reduce the risk of fraud and identity theft, National Insurance numbers can't be confirmed online, although you can phone the tax office and request a written reminder or fill out a form onscreen and post it.
Check all your tax documentation, payslips or official correspondence from the UK tax office, HM Revenue and Customs (HMRC), as your National Insurance number will be shown on them.
Visit the website of the UK Government and navigate your way to the relevant section relating to National Insurance numbers.
Decide whether to contact the National Insurance Registrations Helpline on 0845 915 7006 between 8.30am and 5pm Monday to Friday, and request written confirmation of your National Insurance number, or post your request.
Fill out the two-page HMRC form CA5403 which allows you to apply for written confirmation of your National Insurance number.
Post the form to the HMRC. For security reasons, it may be best to send it by registered delivery.
Wait up to 12 weeks for the confirmation letter to arrive.
If you are applying for a National Insurance number for the first time, then you will need to complete a face-to-face interview with a government employee to confirm your identity. If you have never had a National Insurance number before and are under 20 years of age, you must phone the National Insurance Registrations Helpline for advice. If you have never had a NationaI Insurance number before and are aged 20 or over, then you should phone Jobcentre Plus on 0845 6000 643 for advice or visit www.direct.gov.uk.