Not if it's in a business that you would expect to be open on a Saturday i.e a shop If you work Saturday overtime then yes
RE: Depends on your contract of employment What it is,</p> My days are Monday - Friday only, but i been asked to work Saturday and Sunday for same price</p>
I wouldn't. I'd want at least time and a half. You DON'T have to work the weekend, but you've been ASKED, so you should be paid for unsocial hours.
RE: Depends on your contract of employment If you have worked your contractual hours then it will be considered as overtime. That doesn't necessarily mean extra pay though. Does your contract mention overtime rates? If it does then that is what stands. If it doesn't then the employer are under no legal obligation to pay extra. Up to you to ask. If they say it is single then it is single. Up to you whether you do it or not. Some places offer TOIL instead of extra money. You need to check your contract and then speak to them.