Funnily enough, in 'equality' training on my new job, we were asked to discuss this problem. The scenario was that there is a BNP member on your team who works with absolute professionalism, and keeps his politics apart. A black guy on your team finds out, and refuses to work with the guy, even though the BNP member treats him the same as everyone else (this is hypothetical of course!). If push comes to shove, who do you fire? We worried about the moral issues, the legal question of firing someone for their political beliefs, and considered the likely realities of such a situation. The correct answer though was apparently to just fire the BNP member. If it goes to a tribunal, unfair dismissal compensation would be capped at a few thousand pounds. If you fire the black guy and he succeeds in bringing a charge of racism, the compensation is unlimited. This interesting solution was apparently recommended by an HR magazine.