Sash Window Workshop Ltd and another v King, Mr King was a commission-only salesperson who worked for the window company for 13 years, purportedly on a self-employed basis. His annual leave was unpaid. Some years, he took his full annual leave entitlement, but there were a number of years in which he did not request all of it. He tried not to take too much holiday because, if he was not working, he would not get any commission. When Mr King's work with the company ended, he brought an employment tribunal claim for, among other things, a series of unlawful deductions from wages for holiday not taken. The employment tribunal accepted that both the company and Mr King had mistakenly believed that he was self-employed. He was in fact a worker. The tribunal found that a worker who is unable to exercise the right to take annual leave is entitled to carry that leave forward into the next leave year, even though he or she has made no request to do so. The employment tribunal accepted that the case law on holiday carry over relates to sick leave, but saw no difference in principle between being unable to take paid leave through sickness and the circumstances in Mr King's case.A worker's annual leave can be carried over into the following holiday year if sickness absence prevents holiday from being taken. But what if a worker is prevented from taking leave for other reasons beyond their control? A European Court of Justice (ECJ) case heard on 29 March has the potential to extend when employers must allow workers to carry over holiday.