Magic is like pornography. It is hard to define but we know it when we see it. It is also a very serious subject which often attracts interest that isn’t exactly scholarly. And – which is a problem for books like this one – by its nature, it is a subject that overpromises and underdelivers.

Magic in Merlin’s Realm is a serious book, not a salacious one, but it’s hard to write about magic without a certain nod and a wink – and, of course, we’d all rather have that than po-faced academic tedium. Francis Young has set out to write an occult history of British politics from ancient times to the present – that is, a history which takes magic seriously as an ingredient of politics. Even if he does not actually accept the reality of magical powers – and though he tries his hand at postmodern relativistic teasing, he plainly doesn’t – his point is that lots of political actors have accepted it or have had to deal with people who did. We all now appreciate that you can’t leave religion out of the history of politics just because most modern historians are not actively religious. So likewise, if people in the past took magic seriously, we have to as well.

It’s a good point, given how notoriously difficult it is to define the border between religion and magic. But Young pays less attention to magic’s other boundary dispute, with what we nowadays call science. Political magic was generally practical, not mystical or philosophical: it was used to win wars,