That's the only way, Paul – resist the temptation to engage with them – they're like racists and pro gun control fanatics – they have a very limited focus and they are absolutely persistent. You're not dealing with rational people you can have a discussion with – they have a script and come hell or high water – they stick to it!

The best thing is just to disengage or to not be provoked into engaging with people like this at all.

There is a story about Maya Angelou who won't be in the same room as a racist – she doesn't even say anything, she just walks out.