If you are told about a compulsory service charge, you must pay it, unless the service was particularly poor.
If the restaurant falls below this standard you can refuse to pay some or all of a service charge, depending on how bad the service actually is.
Follow our guide on how to complain if you're told you have to pay a service charge, if you're unhappy with the level of service you receive in a restaurant.
Bear in mind that the quality of service should match the type of establishment you are in.
So you shouldn't expect the same quality of service from a fast food outlet as you would from a restaurant in a five-star hotel.
Some restaurants add a compulsory service charge to your bill, and others leave it to your discretion. In essence you have the right to refuse to pay the service charge in either circumstance if the service falls below a reasonable standard.
If a service charge is compulsory, the restaurant must make this clear before you eat. For example, by stating this on menus it has in the window or by telling you verbally.
If the restaurant fails to do so, then you can argue that the compulsory service charge does not form part of your contract.
If there has been a particular problem with the service, for example, the waiter tipped spaghetti bolognese on you and your clothing, you can claim the cost of having your clothes cleaned.