Some occupations demand that a certain staffing level is required 24 hours a day. These include but aren't limited to: Armed forces and emergency services personnel Seafarers including merchant navy and trawler personnel Domestic servants in private households Senior employees who have the power to set their own hours While people in these occupations may regularly have to exceed 48 hours of work in an average week, these are very much exceptions to the rule. People in 'ordinary' occupations such as office work or factory work should never be asked to exceed the 48 hour average hours figure. It may be the case that you've already agreed to 'opt out' of working a maximum of a 48 hour working week with your employer. However, you can change your mind, provided that you give your employer the correct notice.