"For a start, it would deprive pigeons of a good place to shit on."
Never thought of that.
I think it's not so much a question of statues as coming to terms with Britain's, or any Empire's Imperial past (yet to happen anywhere)
Much of the trouble in the world today, immigration, buying sweated good from repressive countries, arms sales..... relates directly back to Empire days.
The continued glorification of one of the great plunderers of Empire doesn't seem to be a good way of coming to terms with our past - for us or for those we continue to exploit.
Maybe the Irish had the right idea in the sixties   
The solution ?
Jim Carroll