A PLAY, a Pie and a Pint (PPP) – the successful lunchtime play series at the Òran Mór venue in Glasgow – is currently celebrating its 20th season.

Established in 2004 by the late, great producer and actor David MacLennan, this extraordinary institution produces 32 new plays every year (the most of any theatre company in the UK).

Acclaimed for the startling diversity of the work it stages, PPP has spread its wings over the years, creating partnerships with theatres throughout Scotland. Its latest play – The Great Replacement, by Renfrewshire playwright Uma Nada-Rajah – is a case in point.

Following its six-day run at the Òran Mór, the drama is touring to the MacRobert Arts Centre, Stirling and Pitlochry Festival Theatre. Boasting a first-rate cast of Adam Buksh, Hannah Donaldson and Irene Macdougall, this political comedy combines (non-conventional) family drama with the weird, and not-so-wonderful, world of far-right conspiracy theories.

When we meet Fi (a late middle-aged woman of deeply reactionary instincts, played by Macdougall) she is just about to receive an unexpected visit from her daughter Lu (Donaldson).

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Lu and her female partner have decided to try for a child by artificial insemination; which is where Lu’s friend Kal (Buksh) comes in.

Fi is, despite her unconvincing protestations to the contrary, still struggling to accept her daughter’s homosexuality. The prospect of becoming the grandmother of a child conceived with the assistance of a donor who is of South Asian descent sends her into something of a tailspin.

The triangular relations that ensue make for a thought-provoking, improbably funny and, in director Jemima Levick’s smart production, tightly-wrought hour of theatre. The tension and uncomfortable silences between Fi and Lu are the stuff of many a family get together.

The introduction of Kal (who is encountering Fi for the first time) enables Nada-Rajah to open the lid on the can of worms that is Fi’s too impressionable mind.

Thanks to Kal’s seemingly indulgent questioning, we discover that Fi has gone pretty deep into the rabbit hole (indeed, the fetid sewer) of online, far-right race “theories”.

The play takes its name from the white nationalist “Great Replacement” theory, which rolls together antisemitism, Islamophobia and a generalised racism against all non-white people. These days, adherents of the theory tend to blame Jewish business figures (most notably George Soros) for a conspiracy to “replace” white Europeans through non-white migration.

The play deals with Fi’s flirtation with such rancid garbage with an admirable lightness of touch. The presence of a bullfrog from an invasive species (which Lu, who is a zoologist by profession, has borrowed from a lab) is a clever metaphor.

This production has a structural cohesion and a politically incisiveness that were missing from the Traverse Theatre’s production of Nada-Rajah’s play Exodus during last year’s Edinburgh Fringe. Both humorous and important, it provides yet another reason to celebrate 20 years of A Play, a Pie and a Pint.

At MacRobert Arts Centre, Stirling, June 29 to July 1: macrobertartscentre.org; and Pitlochry Festival Theatre, July 3-8: pitlochryfestivaltheatre.com