International students are subject to the same tax regulations as UK citizens. Everyone in the UK who receives an income (money earned) over a certain amount during the year pays Income Tax to the government department known as HM Revenue and Customs. Usually, the more you earn, the more you pay.
Students who work during term-time as well as vacation time will have tax deducted from their wages. However, if you earn less than the personal allowance during the tax year (the tax year starts on 6 April and ends the following 5 April) you will be able to claim back any tax you might have paid. Further details are available at Gov.UK.
When you stop working, your employer should give you a P45 which tells you how much you have earned, along with the total amount of National Insurance (NI) and tax payments taken during the current tax year. The P45 should be given to any new employer that you start working for.
For full and detailed information about Tax and National Insurance Numbers, visit the HM Revenue and Customs website.