This is a fundamental component of the welfare state in the United Kingdom. It acts as a form of social security, since payment of National Insurance contributions establishes entitlement to certain state benefits for workers and their families.
Workers pay contributions from the age of 16 years, until the age they become eligible for the State pension. Contributions are due from employed persons earning at or above a threshold called the Lower Earnings Limit, the value of which is reviewed each year.
Self-employed persons contribute partly through a fixed weekly or monthly payment, and partly on a percentage of net profits above a threshold which is reviewed periodically.
Individuals may also make voluntary contributions to fill a gap in their contributions record and therefore protect their entitlement to benefits.
For more information, check out the Governments website at gov.uk