Regulations may provide that a person shall be treated as capable of work, or as incapable of work, in such cases or circumstances as may be prescribed.

Regulations may, in particular, provide that a person shall be treated as capable of work if he does work of a prescribed description, or more than the prescribed amount of work of a prescribed description.

Accordingly regulations may provide that a person shall not be treated as capable of work by reason only of his doing such work as may be prescribed, or no more than the prescribed amount of work of a prescribed description.