Following a period of sickness absence, when on a phased return to work the employee is effectively alternating between working time for which they would be paid normally and sickness absence for which they would be paid either contractual sick pay under their contract or statutory sick pay (in accordance with the SSP rules). You cannot make an employee take holiday whilst they are off sick – this is unlawful under the Working Time Regulations. The employee can however opt to take annual leave. It is also worth noting that for SSP purposes an employee is deemed to have been incapable of work for the whole day if they arrive for work but do no work before they go sick. But if an employee has done even a minute’s work, that day cannot be treated as a day of incapacity for SSP purposes. This means that SSP would not necessarily be payable where employees are working half days as part of their phased return.