What is Mutuality of Obligation?

Definition of Mutuality of Obligation

Mutuality of Obligation (MOO) is an employment law concept. MOO exists when employers are obliged to provide work and employees are obliged to accept the work provided.

How MOO works

Let’s take a traditional full-time employment example. Jim works for Sarah as a shop assistant. Jim works full-time. As Jim is Sarah’s employee, she is obliged to give him work to do. Conversely, when Sarah offers Jim work, Jim is obliged to accept it. Between Jim and Sarah, employee and employer, there is a Mutuality of Obligation.

By contrast, one-off jobs often have no Mutuality of Obligation. Let’s say David is looking to have his fence painted. He offers the job to Laura, a local painter and decorator. She is under no obligation to accept the work and he was under no obligation to offer it to Laura in the first place. Therefore, Mutuality of Obligation does not exist here.

MOO and the other IR35 tests

MOO is one of three tests used to determine whether a worker falls inside or outside the scope of IR35, alongside the tests of substitution and control. “Substitution” tests whether it would be possible for the worker to provide a substitute in their absence. “Control” gives consideration to how much control the worker has over their day-to-day working practices.