I believe that in some countries the population is more and some people start making abuse of free public things like toilets, so for countries like the uk and europe, we have a community who is less fortunate and the law can not prevent them from causing troubles, some break toilets and block them on purpose and much more damage, and when there is a fee to usage, people get prevented to enter without the need. Basically you paid to get a clean toilet with toiletpaper and water and soap. Which if it was free, the possibility would have been that it was a disgusting messy dump. So britains got a good reason to charge a small fee!