The Tricycle’s excellent “Not Black & White” season - Nicolas Kent’s third “grand projet” this year, following the South African and Afghanistan seasons - wraps with a rapid-fire look at immigration loopholes and supervision as they affect the case of Justice (Aml Ameen) from Zimbabwe.

The wider, more serious problem of how so many immigrants and asylum seekers are unaccounted for, let alone left unmonitored, is not playwright Bola Agbaje’s concern. But in the case of Justice, facing deportation pending an appeal, she drums up a good human story.

As in her first play, Gone Too Far!, Agbaje’s great at setting up funny, rebound dialogue on ethnicity and competitive ideas of nationhood. So we see two black lawyers at spiky odds with each other over who’s more entitled to be here, and a hilarious argument between a Nigerian and a Ghanaian cleaner on the correct provenance of a simple rice dish.

One of the cleaners is also a pastor, who leads his congregation - the entire cast of eight, suddenly transformed into the gospel-singing flock - in praising the undependable Almighty, while Justice’s sister Grace (Sharon Duncan-Brewster) is stymied by the system and then exploited by an Asian enforcement officer (Abhin Galeya) who takes sexual advantage of her.

The plot is interestingly complicated in the edgy relationship of the prosecuting lawyer (Karl Collins) and his office subordinate (Rebecca Scroggs, a terrific newcomer); he’s previously sent down an innocent man who’s committed suicide. This is to show how easily everything can go wrong and illustrates his point that justice is subjective.

Sure enough, Justice finds himself in a Guantanamo Bay torture situation and, although he wins the appeal on health grounds, he decides to cut and run to Holland, much to his sister’s annoyance after what she’s been through.

The 95-minute play errs on the side of sketchiness - next, Agbaje has to build a more concentrated drama, move away from television-style sound-bites - but Indhu Rubasingham’s production is fast and funny, on a simple set of movable furniture and neon lights by Rosa Maggiora, and the acting’s a treat, especially from Cecilia Noble as a truth-telling Momma and Jimmy Akingbola as the ruthless, black British protective letter-of-the-lawyer.