Turin, I guess because that's the way it's written in your contract which is fine. From what Mr. Brown is saying (I think) it is different in his contract, a contract doesn't have to be written it can be based on what's been accepted practice, so if it doesn't stipulate in your contract about public holidays and you have worked the way the company wants it then that's it I'm afraid. If it isn't specific about public holidays it may be worth approaching HR and see if you can get something formally written down.