What goes through the head of an ordinary man in the course of one day (aside from the obvious)? If this seems a quotidian subject, Anthony Neilson’s Realism is anything but. Revived at Soho Theatre, five years after its debut at the Edinburgh International Festival, Neilson’s play is an ambitious choice for new artistic director Steve Marmion to tackle as his opening production.

Ostensibly a one-man kitchen sink drama, Tim Treloar plays, well, Tim Treloar, an unremarkable guy waking up newly single on his sofa one Saturday morning. Rejecting the offer of company, Tim instead chooses to mope around his flat (and mind) where we join him for the next three discombobulating acts.

From childhood memories to sexual fantasies, even imagining his own funeral (and haven’t we all done that?), Neilson pits Tim’s physical and mental realities against each other, showing up our subconscious for the surreal soup it is. Ex-girlfriends compete for mind space with mothers, not to mention spots from Any Questions and the Black and White Minstrel Show. No PC self-editing here.

Compelling and sometimes hilarious in its honesty, it’s nevertheless a complicated portrait to pull off, demanding countless costume changes, sound cues and set pieces, as when characters crawl out of televisions, washing machines, in fact any domestic orifice in Tom Scutt’s ingeniously compact set. Hard to deliver slickly, then, and when pacing is lost, so too are the underlying emotions.

A touching Treloar is supported well by the ensemble cast, especially Golda Rosheuvel as departed girlfriend Angie and Rocky Marshall as Tim’s best mate and – in a scene-stealing cameo – his cat. When Neilson’s coda brings us back to reality not so much with the bump but the bruise of emotional weight, it’s only a shame not to have felt that ache more throughout.