I am pretty sure that if they need you to be answering calls on your time off then they need to be paying you an 'on call fee'. Otherwise, people who work regular hours could conceivably be called at midnight which, I'm pretty sure people would object to.

As for how to approach this, I suggest you do what I did when I was being treated unfairly with regard to my maternity rights and didn't want to rock the boat.

Simply send an e-mail to your HR department asking the question you've asked us here. Explain that you're concerned that these frequent interruptions to your sleep may have an adverse effect on your work performance as you do not feel properly rested.

This will result in two things:

1) You will know for definite what your rights are for future reference

2) When HR find out that your boss/colleagues are doing this, they will make sure it stops for fear of some kind of litigation (assuming, as I suspect, that it is unreasonable) without you having actually put in a complaint against anyone - you have simply asked a question. A lot of time, bosses break employment law simply because they are unaware of what the law is. This way, HR will give them a quick crash course and the behaviour should stop. If it doesn't, I think you're perfectly within your rights to put in a complaint as it's clearly malicious. The result will probably be your boss getting into trouble, not you.

I hope this helps.

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