time spent on call by a doctor in a hospital constitutes "working time" for the purposes of the EC Working Time Directive 93/104/EC, even if the doctor is able to rest or sleep in hospital accommodation during the period on duty.
For relevant general notes see Working Time Regulations/doctors and/or at Specific employments/offshore workers and/or at Working Time Regulations/compensatory rest and/or at Working Time Regulations/problem areas .