It’s fashionable these days to be diagnosing and dissecting the fragile, bruised ego of the modern man. After Today does that for a previous generation, for one man in particular, but one that could stand for many of the old guard – TV presenter Bill Grundy, the man who wrecked his career goading the Sex Pistols into those establishment-rocking live swears on regional news programme Today.

Tim Connery’s first class portrait piece, directed by Doug Kirby, places an embittered Grundy some way into his wilderness years, filming an unwatched lunchtime documentary at Hever Castle in Kent. A young buck producer, Julian, is impressed by Grundy’s on-screen artistry, but increasingly tried by his fractiousness and desperation to get to the local hostelry for a livener. There’s a tide-change in TV and we’re watching it wash Grundy up the shore.

Of course, we need Grundy’s back story too, and rather than have him explain it to an oblivious Julian in awkwardly expositional dialogue, Connery has Grundy delivering it to us as he takes hipflask breaks from filming. In these flashback moments, he lounges in his daytime TV chair working his way line by line through the brief interview, increasingly worked up as he interrogates his own and the Pistols’ motivations, a conversation he must have had with himself many times as his career went down the toilet.

Alex Dee is astonishing as Grundy, oozing TV golden age self-satisfaction, and keeping those plummy establishment tones pitched perfectly. He even stresses “pistols” in the odd way Grundy did in interview. There’s some beautiful turns of phrase here which capture the man – Today is dismissed as a “puddle of piss”, punk was music for the “unemployed to dance spastically to”, TV’s high heid yins smell of “lavender-scented pomade”. The latter, of course, smacks of the thinly-veiled homophobia that he also unleashes on Julian, but with the acidity of the old elite that makes you wonder whether he’s closeting something himself.

Ankur Sengupta as Julian makes for a very good foil. His own character is very softly injected into proceedings, so he’s not mere cipher, but also not interfering with the star of the piece. We find him hovering between admiration for Grundy’s televisual presence and competence, and palpable frustration at his drunkenness.

Dee meanwhile gets two particularly magnificent speeches to make. One, a rant to the younger man about the multiple indignities that middle-age visits on a brittle psyche, and best of all, a room-pacing soliloquy on music that sees the Pistols’ cartoon nihilism as an affront to the majesty of his own cherished Brahms. And yet, somehow, the play keeps us guessing as to what he really feels. He hates them, and yet, in conversation with Julian, his desire to be significant is so strong, he wants to claim that he made them. Victim and offender, as Julian astutely identifies.

The BBC documentary marking the 200th anniversary of The Scotsman praised the sober, responsible, more equal professional journalism of today, but did so with a wistful look in its eye. There was keenly felt nostalgia for the boozy, six hour lunches in the closes of Cockburn Street, and a question hung in the air: have we lost something? After Today does much the same for TV journalism. There’s something raffish and fabulous about a man who can be paralytic at 9am and ready to interview a cabinet minister at 11am, not to mention the other trappings of the old school – the tie and three-piece, the on-air pipe smoking, the casual intellect and classical education. It’s clear to us here that his time has gone, but it’s not a done deal that that’s an entirely good thing.

In pre-publicity, the writer Connery said, “I saw an alcoholic, bitter character with absolutely no redeeming features.” That’s as maybe, but somehow he’s still used him to produce a play full of nuance. Plus, pop nerds, it opens and closes with an untelegraphed riff from the Television Personalities’ Where’s Bill Grundy Now?, the kind of subtle attention to detail which has been evident throughout.