Coined, as it was, by a dead white man whose oeuvre is considered one of the crowning achievements of Western civilisation, the expression ‘hoist by his own petard’ must be fast approaching its use-by date – the thin end of a wedge which will one day see the expulsion of the entire Shakespearean canon from our schools, the revoking of John Bell’s National Treasure status and the rebranding of two cigars (five points if you can name them).