@DGRossetti
Art goes where it fits in the time. A few of these artistic masterpieces (are they listed in every guide to Britain - our own rival to Michaelangelos David - on Thames ?) are fortunate enough to have survived long enough to see society change around them.
There's lots of old art in museums. And if Britain hadn't nicked quite so much from around the world, there would be room for lots more.
I don't think that museums should become lumber rooms for art that, due to entirely knee-jerk political reasons, has been relegated to League Two, so to speak. If you have the appreciation of art that your username suggests, you ought to accept that one of the things that makes art work is its setting. A statue of some long-dead bloke who was in fact a massive arsehole can actually perform a useful social function in beautifying its locality. If such a statue were to be moved, it reduces the artistic merit of the statue and the beauty of the location. Furthermore, I don't believe that it would be replaced with something that people would like, given the direction that art generally has gone in, that is to say, elitist and obscure. But even if I'm wrong, and public art now is as good as its ever been, that's not an argument in itself for removing any particular statue or monument.
I'm not suggesting that politics doesn't matter at all. You mentioned a Nazi flag, and someone on another thread asked me "what about a statue of Goebbels". Well, my answer to that would be that people who suffered through WW2 are still alive, even a few of the perpetrators are still alive. I'm not aware there are any statues of Goebbels in public anyway (by the way - there are statues of Mao - google is your friend). And my answer would be that it would have to be an absolutely magnificent piece of art to overcome the awfulness and the recentness of the events those things would bring to mind. It is possible though - look at the Olympic Stadium in Berlin or the Milano Centrale railway station. Both are buildings that scream "fascism" and yet I think it's right that they still stand because they are very impressive. I know a building isn't the same as a statue but I think the parallel is a fair one.
Moving statues from plinths into museums seems a jolly good British compromise. Because there are some countries that would destroy them, and there are others that would ring them with armed guards and minefields.
Well, I think that's where the statue of Colston is heading. But I would say that the reason the British haven't destroyed their statues is because for the most part the UK is, comparatively speaking, a country that has been sufficiently well-run not to require all that much civil disobedience.