In his new all-male staging of the play at Shakespeare's Globe, Mark Rylance does not have to go to such costly lengths to create this crucial presence. Indeed, with a courtyard full of groundlings at whom Brutus and Mark Antony can direct their political make-or-break funeral orations, you could say the situation is amusingly reversed - a large proportion of the audience here is paying for the privilege of impersonating the throng that rhetorical skill so easily turns into a mob.
Julius Caesar was one of the first Shakespeare plays to be staged in the newly built Globe precisely 400 years ago (a Swiss doctor, Thomas Platter, wrote approvingly of a performance in "the straw-thatched house" on the south bank of the Thames), so it makes a fitting start to what is being billed as an "anniversary season".
Certainly, the piece, "in theory, at least", is uncommonly well-suited to the space. Rylance's production follows the practice of having the Romans dressed in contemporary Elizabethan garb (ruffs et al) with antique adjustments, like the togas that are tied over this attire in the assassination scene. Here, though, there is a triple time-frame effect, for the voluble cast members planted around the audience are camouflaged in present-day mufti, with reversed baseball caps etc.
The inn-yard intimacy of the Globe's architecture has, in the past, encouraged a potentially dangerous atmosphere of ugly partisanship. Ironically, there was precious little sense of mob danger at the first night of Caesar. While the plants from the cast, aroused by the sentimental pitch from Mark Lewis-Jones's ranting, unshaded Antony, urged torchings and insurrection, the punters stood by as phlegmatic as statues, apart from when switching off their mobile phones or wandering back with refreshments.
Perhaps they were overcome by embarrassment at being directly recruited. The heckling was eerie only by its complete absence. Meanwhile, the audience's representatives on stage were busy kicking Cinna the poet to death.
The Elizabethan dress brings home to you what a live and touchy issue the play's subject - the ethics of tyrannicide - must have been for the original audiences. The scene where the conspirators gather in Brutus's orchard put you in mind of The Gunpowder Plot.
But in other respects, this is a decent rather than an exciting Julius Caesar. Richard Bremmer makes a mordant impression as a suitably lean and gloweringly resentful Cassius, and Danny Sapani radiates a naive and self-deceived honourableness as a youthful Brutus. It would be good, though, to see a production at the Globe that had had the attention of a top-league director.
To 21 September, 0171-401 9919. A version of this review appeared in later editions of yesterday's paper