Steve Waters’ plays tend to deal with political issues in a hard-hitting, but entertaining, way, presenting them via vivid individual decisions and confrontations, with plenty of humour to leaven the drama. Sometimes, however, the narrative and the polemic don’t cohere with complete conviction.

So it is with Fast Labour, his take on the exploitation of illegal immigrants from Eastern Europe, premiering in a joint West Yorkshire Playhouse/Hampstead Theatre production. The final stages take on a sentimentality and melodrama at odds with the gritty realism of the lengthy first half. For all that this is an ambitious and intellectually honest stage realisation of a problem that admits no glib answers.

Waters cleverly blurs the “them-and-us” element of the problem by making his protagonist, Victor, a Ukrainian illegal with entrepreneurial ambitions and a past history as a businessman. A desperate scrap of humanity, he is found a job in a fish processing plant in Scotland by gang-master Grimmer. Gradually, with two of his Eastern European colleagues, he moves down to East Anglia and up in the world, founding his own company, Fast Labour, to co-operate with, then challenge Grimmer’s combine. Finally, things unravel, sometimes predictably, sometimes more unexpectedly.

The play raises teasing questions of truth and lies, the nature of loyalty, honesty and integrity. In particular these arise through three contrasted immigrant workers who, by the end of the play, are seamlessly transformed from their earlier selves: Victor (Craig Kelly), the dangerous optimist, unable to satisfy or ignore his conscience, Moldovan Alexei (Roger Evans) who combines a capacity for loyalty with a violent temper, and Andrius (Joseph Kloska), the Lithuanian whose intellectual tomfoolery turns into contempt for his fellows.

Kelly, Evans and Kloska inhabit their characters with total conviction, Kelly’s insouciant charm adding further confusion to the moral landscape, and Mark Jax’s Grimmer completes a powerful central quartet. Though nicely contrasted, the women are less convincing, Kirsty Stuart’s semi-innocent Anita changing, rather than developing, and Charlotte Lucas (Tanya) taking a rather one-dimensional role in the overwrought climax.

Despite imperfections, Fast Labour impresses as a play that takes its subject and its audience seriously. We are expected to do our share of the work, as in following the unexplained switches from English to “Russian” (English, but spoken more fluently and with British regional accents). Ian Brown’s production is straightforward and clear and Simon Daw’s designs economical and effective, with neat use of video backgrounds.

- Ron Simpson