The Advocate General of the ECJ has given an opinion that is likely to disappoint many employers. Her opinion, which, though not binding, is nearly always followed by the ECJ, states that workers should be allowed both the holiday entitlement for the period during which they are out of work on sick leave and payment in lieu if they have been fired. The Advocate General says there should be no confusion between sick leave and holiday, and that the two must never run concurrently. “Sick leave and annual leave serve different purposes and therefore must not for legal purposes be regarded as interchangeable,” she wrote. The case concerned a number of UK HM Revenue & Customs’ (HMRC) employees who were on sick leave and who issued tribunal claims against HMRC under the Working Time Regulations 1998 (WTR) to assert their rights to take leave or, in the case of those dismissed, be paid in lieu of leave. Their claims were upheld by the original tribunal, but the CA rejected them. When the case reached the House of Lords, it asked the ECJ to interpret the Working Time Directive from which WTR came. The problem with the Advocate General’s opinion is that it gives rise to a number of uncertainties. It is unclear, for example, whether there is any limit on the right to take holiday once the worker is fit to return to work or to be paid in lieu if the employment has terminated. Can employees who have been on long-term sick for two years take two years’ worth of statutory annual leave when they return to work from sick leave? Are they entitled to be paid in lieu of that holiday if employment is terminated? It remains to be seen whether the anticipated ECJ decision will clarify these issues.