Macbeth at the Donmar Warehouse review: David Tennant gives his all but play undone by overarching gimmick

One child actor plays the beloved sons of Banquo, Macduff and Siward, and reminds the Macbeths of the heir they clearly lost. The Macduffs are a constant, contrastingly affectionate background presence in the early scenes. Only one of the murders Macbeth commits or commissions happens onstage. We don’t see Banquo’s ghost but hear his groans, which sound like something from a bad porn film.