Opening with the portentous thunder of Carl Orff’s ‘O Fortuna’, Jason Byrne’s show at the Athenaeum pins the audience to their seats as though we’re on a nuclear-powered roller-coaster. The Irish comic’s rapid-fire delivery and genuine engagement with the crowd mean that we’re willing to follow him down the most ludicrous of digressions. His demented, hysterical stream-of-consciousness wanders regularly into territory that’s not safe for work, home, mums (as one delighted but alarmed 19-year-old discovered) or even Byrne himself. In fact, Jason Byrne seems as scandalised by his own routine as any one of us watching the madness unfold.

It’s that manic glee that makes Jason Byrne’s show feel like a comedic knife-edge – Byrne is like a mischievous kid that can’t quite believe he’s getting away with it. A bonkers rant taking in the Australian climate, family holidays, and ‘touching up’ the Pope is rounded out by Byrne lunging at audience members with ludicrous three metre arms and cackling like a madman.

This show isn’t for the faint of heart, though. Byrne is gleefully rude, often scatological, and his rambling style can lead to material which may offend. The charm, though, is in the comedian’s obvious delight in stopping himself, declaring “I can’t believe I just said that. My God, I’m going to Hell”, then carrying right on in the same vein. Family photos and a hilarious discussion of his childhood are charming and scandalous by turns, and while it seems to come too soon, Byrne’s trademark, lunatic finale is a gift.