National Insurance number
The National Insurance number is used as a reference number in the Pay As You Earn system, and also by the self-employed. It is also used in applications for Individual Savings Accounts (ISAs), to check that an individual has opened only one ISA in a tax year.
Social Security (Scotland) Act 2018
The Social Security (Scotland) Act 2018 is an Act of the Scottish Parliament to allow for the devolution of aspects of the social security system to the Scottish Parliament as part of the devolution settlement agreed by the Smith Commission after the independence referendum in 2014.