Laplandsql, I am not sure why there is a charge in that Edinburgh mall for using their toilets. However, at Tower of London, I have a couple of ideas. One is that Tower of London has had a vandalism problem in recent years. Strange but true. One of the places they can get easy access to is the toilets and maybe the charge is just to discourage them a bit. Not very likely with the 50p charge but at least a slight deterrent so that the people who use the toilets properly might not be missing toilet paper or functioning air dryers or soap. Two, it is rather costly to maintain the Tower of London, hence the entrance fee charge and maybe this extra small revenue stream pays for the upkeep of the toilets they have installed in there (flushing toilets not being a common feature of an original medieval castle). A lot of the free public toilets in London have been vandalised to the point they have been shut and now we have those portable loos (which are private) which usually charges a small fee. I totally sympathise with the toilet situation you encountered in London. The number of muffins I have had to buy at Starbucks in order to use their toilet have made me put on weight.