In the UK, restaurant menus show the actual cost of the meal including all taxes, and where there is an included service charge, quite a regular thing for parties of 6 or more, the percentage (usually 12.5%) is clearly indicated. Even where there is an inclusive service charge, this can be questioned by the customer, and can be reduced for bad service/ disappointing meal, or increased at the customer's discretion.
What is irrtating is when an establishment has added their inclusive service charge - they then leave the option to add a tip open or blank in the hope that the customer will add more.
Quite a few establishments close the slip so a tip CAN'T be added if you want to pay by card, so presumably the waiters can take a cash tip left on the table.
Yes the prices are higher than they are in a comparable establishment in the US, but those low prices don't include the state taxes or the almost mandatory tip.
What I found disappointing in one hotel we stayed in last summer was that our waiter actually looked disappointed with the $100(20%) tip he received at the end of our meal. If all his tables were as generous, he would have earned well over $1000 in tips at the end of the evening, on top of his minimum wage. Multiply that by 5 days a week and he would be on $5000 minimum a week or based on a 48 working week year - nearly $250,000 a year! Believe me - that is a pretty good wage to be on for anyone - never mind a waiter.