At times, this production of Little Eyolf, Ibsen's late play about family relationships is almost literally terrifying. Indeed, callow theatregoers might be safer foregoing the eruptions of a stormy marriage driven beyond endurance by tragedy. Those with stronger constitutions will relish the chance to see a family imploding as secrets emerge to make times that are already bad worse.
One imagines that this residency at Jermyn Street might be the prelude to a trip to a larger house and, judging by the big, effusive acting, director Anthony Biggs has already asked his cast to perform based on that assumption.
Tragedy happens repeatedly to Alfred and Rita Allmers so that it almost seems habitual. In Michael Meyer's translation, which has acquired classic status, we see them evading responsibilities, which return their neglect with fearsome interest before a Chekhovian ending when the couple finally accept that life is there to endure rather than enjoy.
They must have been happy once but the birth of their eponymous little boy heralded a series of disasters that would be enough to wreck any family, let alone one as fragile as this.
Biggs should be proud to have attracted such a strong cast to this tiny theatre. Imogen Stubbs pulls out all the stops as a histrionic Rita Allmers, a wife who can never forgive herself for an accident that left Eyolf, played at this performance by a confident Finn Bennett, a cripple.
In fact, she and her writer husband, Jonathan Cullen's almost schizophrenic Alfred, were equally responsible for leaving their baby son alone while they enjoyed a few stolen moments of passion.
A decade on, it seems that both father and son are more in thrall to Alfred's half-sister Asta than his wife. Holby City favourite Nadine Lewington in this part gives a more measured performance that her colleagues, impressing with her understated realism.
After a visit from the sinister Rat-Wife, a second accident drives this trio close to madness, which had anyway been awaiting the family, or so it seemed to those of us packed into such close proximity with them in the claustrophobically small space.
Ibsen always steps up a gear when the worst finally happens and the Allmers' reaction to stress is almost too heart-rending to take in.
It is hard to leave any performance of Little Eyolf other than in a state of shock and the involvement that one feels when the actors are only a few feet away throughout cannot be overstated.
It would be no surprise to see a transfer in due course and that will provide a good opportunity to judge the performances in a more fitting setting.