Simon Russell Beale is fond of describing acting as three-dimensional literary criticism. And in my personal experience, the most mind-expanding insights into Shakespeare have come from actors in the rehearsal room, usually without the long introductory preamble with which directors generally preface even the most banal of suggestions. As a tribe, we can barely ask an actor to move to the left without making a speech about it – but actors just get on with it. One day in rehearsal, without warning, David Calder – who played Polonius in Hamlet – approached the end of his speech of advice to Laertes and flinched. He seemed to dry. And then, under the heavy weight of what felt like deep personal shame, he said: “This above all: to thine own self be true,/ And it must follow, as the night the day,/ Thou canst not then be false to any man.” From the heart, like many fathers, Polonius wants his son not to make his own mistakes. But, mired in a corrupt court, he is incapable of dealing truthfully with others, and of being true to himself. And Calder’s Polonius knew it.

It would be equally plausible to present the Polonius of tradition, a man devoid of self-knowledge, puffed up with self-regard. But I was electrified by Calder’s illumination of three lines worn thin by their relentless repetition, out of context, often by habitual liars. I knew immediately that the Calder Polonius had helped Claudius assassinate the old king, and was tortured by his own treachery. I started to think that the old king was probably a disaster for Denmark, that – like Richard II – he had to go. This was the real Shakespeare: an actor who provides for other actors a myriad of ways of telling his stories and of being his characters. His intuitive openness to interpretation is mistaken for complexity. His relish for ambiguity is taken as a challenge to those who would pin him down. But they are functions of his calling: he writes plays.