When you have to pay a service charge
Some restaurants add a compulsory service charge to your bill, and others leave it to your discretion. If a service charge is automatically added the restaurant must, by law, warn you of this before you eat.
The charge must be clearly indicated before you get to your table (either outside the building or immediately inside the door) as well as on the menu.
What it the service is poor?
If you are told about a compulsory service charge, you must pay it, unless the service was particularly poor. If this is the case, you can refuse to pay some or all of it.
But 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 burger joint as you would from a restaurant in a five-star hotel.
And you can't refuse to pay some, or all, of the food component of the bill if the problem was only with the service.
If no service charge is shown
If the compulsory service charge is not clearly shown you are within your rights not to pay it, for example, if you thought the service was substandard.
You could also report the restaurant to Trading Standards as unclear or misleading pricing is a criminal offence, according to the Consumer Protection Act 1987 and the Price Marking Order 2004.
Which?