The weekly maximum working hours
Usually adult workers cannot be forced to work more than 48 hours a week on average - this is normally averaged over 17 weeks. You can work more than 48 hours in one week, as long as the average over 17 weeks is less than 48 hours per week.
Your working week is not covered by the working time limits if you have a job:
where your working time is not measured or can be determined by you (eg a managing executives with control over their own decisions)
in the armed forces, emergency services and police - in some circumstances
as a domestic servant in private a household
certain categories of seafarers, sea-fishermen and workers on vessels on inland waterways
If you are a trainee doctor the 48-hour maximum working hours applies to you.
Opting out of the 48 hour week
If you are 18 or over and wish to work more than 48 hours a week, you can choose to opt out of the 48 hour limit. This must be voluntary and in writing. It can't be an agreement with the whole workforce.
You shouldn't be sacked or unfairly treated (for example refused promotion) for refusing to sign an opt-out.
You can cancel your opt-out agreement whenever you want - even if it is part of your employment contract. However, you must give your employer at least seven days notice. This could be longer (up to three months) if you previously agreed this in writing with your employer.
Your employer is not allowed to force you to cancel your opt-out agreement.