National Insurance contributions (NICs) are payable by anyone in work (employed or self-employed) whose earnings or profits are above certain limits. The amount you pay depends on the amount of your earnings or profits.
There are different classes of NICs depending on whether you are in work or you work for yourself. If you are an employee, your employer will deduct NICs due on your wages and pay them over to HM Revenue and Customs.
Your employer has to pay contributions based on your earnings at the same time. The NICs you pay are worked out on your gross earnings before tax. Your contributions provide for certain unemployment, sickness, maternity and retirement benefits. Whether you are entitled to NI benefits depends on the contributions you have paid into the scheme.
Each of these benefits has its own different 'qualifying conditions', which must be satisfied before payment can be made.