I don’t know if Mike Bartlett, the author of this 35-minute play, goes on demos in a Batman suit; but he might have composed it while he was perched with a Fathers 4 Justice placard at the top of Tower Bridge. That’s a compliment to his writing, because My Child is almost as tough and passionate as Strindberg’s Father, and not a compliment, because it’s as unbalanced as, well, Strindberg’s Father.

For no clear reason, part of the Court’s auditorium has been temporarily converted into a traverse theatre that resembles a blend of tunnel, Tube train and American-style bar. The spectators perch on stools or stand in front of big, garish ads watching actors who spend much of the evening scattered among them.

Does this increase the intensity of Sacha Wares’s production? Well, Bartlett’s dramatic manipulations left me wanting to strangle Lia Williams and buy a consoling drink for Ben Miles.

Williams’s Woman is doing all she can to ensure that her exhusband, Miles’s Man, is “erased” from the life of their nine-year-old boy, Adam Arnold’s Child. Father-style, she says he may not be his son and, Kramer vs. Kramer-style, uses a bruise on the lad’s arm to suggest that he’s an irresponsible parent.

Everything becomes a weapon, even Miles’s bungling attempt to get help from Sara Kestelman as his former mother-in-law. And Williams’s venom is matched by Arnold, who now sees his father as a loser who won’t buy him expensive gadgetry.

Bartlett’s brusque, overlapping scenes culminate in a denouement in Scotland, where Miles’s increasingly desperate, forlorn Man has abducted his son, and an ugly fight with Adam James’s slick, mean Karl, who is Child’s stepfather and, perhaps in tribute to his dominance, the only character with a nongeneric name. Here Bartlett’s true targets become clear: the unscrupulous mum who spoils her child, the rich slicker who teaches him macho values and mean modern Britain.

Poor old Man, who is left ruefully wishing that he didn’t still believe in books, trainspotting and “trying to be moral and good, not selfish”. Thanks to Miles’s fine performance, you see what’s hapless and inadequate in him, and thanks to the excellent young Arnold, you see the thwarted affection in the brattish child. My Child is Bartlett’s debut play, and he’ll doubtless write more subtly in the future. But it’s a punchy start to a promising career.

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