Part 2, Chapter 7 Income Tax (Earnings and Pensions) Act 2003, Part 2, Chapter 7, section 44(2)(a)

Social Security (Categorisation of Earners) Regulations 1978, Schedule 1, Part 1, paragraph 2

For the agency legislation to apply, it is necessary to consider whether someone has (or has the right of) supervision, direction, or control over the manner in which the worker provides their services to the client.