can I refuse to serve a customer?

[AIM]

Are you the shop owner/leaseholder? If so you can ban them from the premises.

You can always refuse to serve a customer, no rights are required. Being a shopkeeper is not a duty it's a job and you can always refuse. All that happens is that you lose a customer.

Edit: A lot of people are saying only the manager can make such a decision, that's not true. You may well get in trouble with your manager for making your own decision, you'll certainly have to justify your decision to your manager and you may lose your job, but you can still say no. YOU CAN REFUSE to serve a customer.