Nigel Farage has just met one of the most fascinating aspects of modern politics.

He was surrounded in Edinburgh by left-wing 'anti-fascists' shouting 'Racist scum. Go back to England'. The same mob also screamed 'scum' repeatedly at the top of their voice until they made him leave. This is probably the best demonstration so far of something which has gone un-remarked upon for too long.

Among the closest thing we have to fascists in modern Britain are people who call themselves 'anti-fascists'. Not all people who call themselves 'anti-fascist', thank goodness. But a sizable portion. If you ever see these people in action you will notice that they behave in exactly the way you would expect their alleged opponents to behave. It is not just their behaviour (screaming, shouting, marching, fighting, threatening, brawling etc) that is so evocative of fascism. It is the belief that their rigid belief system is the only correct one and that all opponents are 'scum' who must be 'smashed' (this really is the language they use).

Their targets now include people who are actual anti-fascists. I have written here before of how Hope not Hate, an 'anti-fascist' group took it upon itself to publish a top-ten hit-list of 'Islamophobes', one of whom - a Danish journalist and free-speech advocate - was subsequently visited by an assassin. In recent weeks Hope not Hate have been mulling over whether to campaign against UKIP as well as the BNP. By crossing such lines 'anti-fascists' do more than strip terms we need of any meaning. They turn language and politics upside down.