Unflinching, excoriating and lethally funny ... Fleabag.

Phoebe Waller-Bridge’s audacious comedy returns with a family dinner from hell, a brawl and a hot, smoking priest. We should have known

If you are a Fleabag devotee, you could only find yourself whispering in reverential awe as the opening episode seated our antihero at a family dinner next to … a Catholic priest. “Oh,” I found myself murmuring and, as Fleabag looked meaningfully to camera, I mentally bowed the knee. “Of course.”

As soon as the emotionally pulverising end of Phoebe Waller-Bridge’s first series about the super-combustible eponymous thirtysomething was revealed, fans wondered how there could be a second run. Where could she go from there?

Desecration makes perfect sense. Defilement and corruption of the divine. We should, we see as she watches him drink and light up a fag, have known.

The priest, played by Andrew Scott with his customary acuity and lightness of touch, is at the dinner table because time has moved on by just over a year and he is to marry the newly engaged couple; Fleabag’s useless father (Bill Paterson) and malignant godmother (the Oscar-winning-since-last-time Olivia Colman). Across from her sit brittle, unforgiving sister Claire and brother-in-law, Martin, whom we last saw trying to kiss Fleabag then persuading Claire it had been the other way round. The air is thick with bitterness, rancour and betrayal even before anyone speaks.

But oh, when they speak …

It is, in short, an immaculately scripted (by Waller-Bridge) and performed (by everyone) half-hour – certainly up there with the best of the first series, and probably up with the best of TV comedy-drama entire. Waller-Bridge’s dialogue is whetted to such a fine edge that you hardly notice when it strikes – you’re too busy laughing at the joke, the audacity – until the blood starts to well up in the wound a second later. Someone remarks that Claire looks happy, and she says she has worked hard at it. “It’s not just about eating and drinking well either,” she says, looking daggers at Fleabag who has tried purging her sins via a health kick since we last saw her. “Putting pine nuts on your salad doesn’t make you a grownup.” “Fucking does,” mutters Fleabag, whose natural state is mutiny. Claire returns to the point when it turns out that their father has not given Fleabag the expected cheque for her birthday, but a voucher for counselling. “I don’t believe you can pay your problems away,” says Claire. “You have to face who you are and suffer the consequences. It’s the only road to happiness.” “Maybe happiness isn’t about what you believe but who you believe,” snaps back Fleabag, flaying skin with every word.

Only in Fleabag’s world does the revelation that the priest doesn’t have any contact with his family because his brother is a paedophile come as light relief. “I am aware,” he says helpfully, “of the irony of that.”

After the flaying, Claire runs to the loo. Fleabag follows. “You’ve been ages. Are you pissed off or are you doing a poo?” In fact, she’s having a miscarriage and her refusal to tell anyone or go to hospital plays out, unbelievably and yet perfectly credibly, as farce. Fleabag claims it is she who has miscarried and Claire insists with heartbreaking fury that “it’s gone, it’s gone” and there’s no need for a doctor. Dinner ends with a literal family fight that sees at least three people going home with bloodied noses.

Everything is here in this densely packed 30-minute nugget. Laughs that come from the deepest part of you, where your better judgment flails and fails. Waller-Bridge’s fleetness as she pivots to camera and back, capturing her tiny moment each time, so we see her in the round and cannot help but follow her wherever in her awfulness she leads. The vivid portraits of human frailty, weakness and – in Martin’s case – near-evil (his toxicity here was so potent it was almost visible; if the priest had performed an exorcism instead of ordered pudding it would not have gone amiss) drawn with just a handful of lines each from an unflinching, excoriating, lethally funny writer whose performers knock every one out of the park.

The priest waits for her outside the loos while Fleabag mops up her bleeding face and hands her his card in case she ever needs to talk.

So. Series two. Faith v Fleabag. Sacred v profane. The hallowed v the unholy fuckup. Good luck, God. You’re going to need it.