Crunch Time, among Williamson's works exploring the dialectic between emotional instinct and rational analysis, is really two plays in one. The first of the interwoven strands concerns parental favouritism and consequent sibling rivalry, and the second concerns assisted dying. The play's heft, and impact, lies in the latter strand.

Williamson's trademark sense of dramatic irony is lively to the end, as when Steve (John Wood), the dying father, contemplating which of his warring sons to fire for the benefit of his engineering empire, says to his wife Helen (Diane Craig), "Whichever way it goes, I want to make sure emotions don’t enter into it."

David Williamson's trademark sense of dramatic irony is lively to the end.

Of course they don't just enter, they explode. Steve fires the older, nerdy, hyper-intelligent Luke (Guy Edmonds) by letter, crowning a painful history of Jimmy (Matt Minto) being favoured, thanks to his supposed charisma (which we don’t witness) and sporting prowess. The family is torn apart as Luke nurses a grudge that grows into a black hole of resentment. The marriages of both sons dissolve, Jimmy's due to his philandering, and Luke's because Lauren (Emma Palmer) needs more of a go-getter than a husband who'll renounce his inheritance rather than reconcile with his father.

But the seams in this sibling-rivalry strand show. You feel your response buttons being pushed, instead of it happening by narrative stealth, and the actors sometimes seem to be fleshing out sketches of characters that have been pasted on to the play, while the real story lies with Steve's cancer and desire to die. Whenever that strand is to the fore, the stakes go up, taking both the writing and the performances with them.