The toilet situation in Europe is pretty bad from the few places I've been: France, Italy, Greece, Spain, UK.
You can't find clean, free toilets and there is a line to use many of the toilets all the time. Most toilets do not have disposable seat covers, some don't even have toilet seats, some don't have toilet paper, etc. It is a sad state of affairs and makes me miss the much better (though still lacking) situation in the US.
Perhaps it is area dependent in UK. When I lived in the North I think access to toilets was a lot worse than down South. We went visiting to many tourist places like the east coast, Yorkshire moors, various historic places. All these trips had to be planned carefully as usually there were no toilets available. Even in food places in such tourist areas. The only place one could always find a toilet at were petrol stations. Another thing is toilet availability for people going for a night out.
In contrast when I lived in London I always felt access to public toilets was pretty good. There were lots of places like McDonald's, Starbucks etc that always let the public use their toilets for free. Then there are free toilets on many large rail stations past the barriers as well as paid toilets before the barriers. Finally there are free standing paid toilets dotted around the city. Back then one had to put a coin to open them.
Personally I think London is one of the better European cities in this regard.
