When I used to research and write about historical anti-terrorism (The Origins of the Vigilant State, Plots and Paranoia), the term ‘terrorism’ had a specific and quite limited meaning. It didn’t cover all violent political activities, even assassinations, if they were directed against political enemies, or for a particular and well-defined political end; but only actions which were designed to terrorize whole populations, in order to make them less supportive of those enemies. (Some violent acts of course could do both.) So, a bomb placed in a café or a concert venue, killing indiscriminately, would qualify (and there were some of those in the late nineteenth century, as there are today); but not the murder of kings or generals, or (to cite a modern example) throwing paint over military aircraft.

Nowadays the word is used far more loosely; but surely not loosely enough to apply to Palestine Action, a march in support of which in London on Saturday led to the arrest of 500-plus demonstrators – many of them elderly – on charges of ‘supporting terrorism’. Painting airplanes, whether you approve of it or not, surely doesn’t qualify as ‘terrorism’ by any definition of that word. The Home Secretary has told us that she knows of other activities that Palestine Action indulges in that make it more dangerous to the common weal, but which she can’t vouchsafe to us yet. So we’ll just have to wait. In the meantime, the events of Saturday do seem somewhat incongruous – to put it mildly – for a Labour government, and in particular for an ex-barrister prime minister who used to specialise in human rights law. Critics suspect, of course, the ‘Israel Lobby’.

Incidentally, the word ‘terrorism’ was first used – in French revolutionary times –  to describe actions not by protestors, but by authoritarian governments, in order to cower opponents into submission.