In this hypothetical situation am I black or Jewish or of otherwise ethnic origin? If so I, maybe they would refuse to work with me? Problem solved. Umm otherwise if we're talking about me being me, I can't really say for certain as I've never been in a situation quite like that myself - I regularly encounter ignorant opinionated morons and while it's all just opinion I let them have their opinions. I (naively I expect) believe in live and let live, that applies to people's radical political beliefs too. However, if push came to shove and the BNP crew member was being offensive to myself or a colleague or a patient then I would confront them and bring it to the attention of a supervisor and follow the chain of command with an official complaint. In other words I would see how the situation played out before making any decision.