Clearly this will depend to a degree on terms and conditions in any written contract that the employee has signed but how enforceable is such an agreement? What actions can an employer take in the event that the employee just doesn't turn in? In the present case it's not exactly a major city banker we're talking about but a nursery nurse on a part time 27 hours a week contract with only occasional bits of holiday pay. As I see it the only sanction they could reasonably use would be to refuse to give a reference. There is no pay owing, she doesn't get paid for the school holidays.