I would say most don't only the more expensive/higher end restaurants and I don't like the fact that they add it on thinking it fine to start encouraging this tipping culture business and makes it awkward for customers who don't agree although for poor service I wouldn't hesitate for them to remove it. In the UK it isn't expected and there isn't a big wage gap like in other countries, not as good as Australia but still better than some countries, that said if someone does an excellent job then you can reward people but don't feel like you have to.