National Insurance

National Insurance (NI) is a form of tax charged in the United Kingdom on employees, self-employed people and employers. Payment of this tax is usually referred to as a National Insurance Contribution (NIC). National Insurance is the Government of the United Kingdom's second-biggest source of revenue.
National Insurance is connected to the welfare state in the United Kingdom, since payment of NI contributions establishes entitlement to certain state benefits for workers and their families.