Under the Working Time Regulations 1998 (WTR 1998), SI 1998/1833, a 'night worker' is one who: • 'as a normal course' works at least three hours of their daily working time during night time, or • is specified as a night worker in a collective agreement or workforce agreement ‘Night time' is, by default, the period between 11pm and 6am. This can be varied by a relevant agreement (eg a contract of employment) to be any period which: • is a period of not less than seven hours, and • includes the period between midnight and 5am A person works hours 'as a normal course' (without prejudice to the generality of that expression) if they work such hours