As I have said repeatedly I feel the UK has a very good system, tips are not expected and there is no moral obligation to give them unless you feel you got good service (even then some people don't tip).
I have noticed over the last few years however that some places in city centers (liverpool, birmingham + london) are becoming more "American" by which I mean they either ask you how much of a % tip you are leaving or even add a tip to your bill unless you tell them not to ( I believe it was 15% at the last place that did this)
This shit needs to stop and it would go a long way if some of the more sensible "mericans" in this forum could start educating the masses in your own country because it makes me feel stingy to tell waiters I am not giving them a fucking £10 tip for the less than 10 minutes they spent taking my order, picking drinks up from the bar and bringing food to my table. I will usually leave a minimum £5 tip on this sort of meal (£30-£60) which would mean they could easily earn £100-150 for a 3-4 hours shift if everyone else tipped at the same kind of rate, but when they pull this shit they get fuck all. Keep in mind these meals are for myself only while I am working away from home and the tip comes out of my wage while the meal is paid for by the company I work for. I have no choice but to eat out in this situation, it is not done for pleasure as I am 100+ miles away from home.
I know for a fact (well it was in the news for what that is worth) that these establishments were paying the staff their wages completely out of the tips to make them up to minimum wage after they had deducted a 50% "administration charge". Hence the fact I am so opposed to leaving (large) tips in this situation.
I only go to these types of restaurants once and I make it very clear that I will not be returning and why for what it is worth.
P.s before you start calling me a tightass a couple of weeks ago I took my wife out for a decent meal the bill came to about £140 with drinks and I left £180 and a few pounds in change with instructions to split the tip between the server (very polite young lady who was more than happy to spend extra time talking about the specials and go into the kitchen to ask the chef questions if she wasn't sure on something) the bartender (excellent knowledge of wines to compliment our meal and whiskies for me afterwards) and the chef (food was amazing).