All these things that I have done

I can't help being amused by this question. I know this question is specifically for this issue and British society in particular, but I think the question was definitively answered by the civil rights movement in the US (and for the US) for a different host of discriminatory 'traditions.' Boycotting played its part in moral suasion (with little larger financial impact, when the market was already profiting from an apartheid system that had traveling bluesmen sleeping in their cars or bus stations, not hotels), but ultimately corrective legislation was required.