STUDENTS AT WORK More help and advice If you don't have your National Insurance number (or you can't find it), call the helpline on Tel 0845 91 57006 or 0845 91 55670 If you have a tax reference number, you can find out which Tax Office will be dealing with you by clicking here If you don't have a tax reference number, you can call in to your nearest HM Revenue & Customs Enquiry Centre for assistance The Inland Revenue's website for students is at www.hmrc.gov.uk/students		If your employer is sponsoring you while you're studying full time find out if you can be paid tax and NIC free