Transferring from the Orange Tree in Richmond to the St James Theatre, Invincible by Torben Betts examines class and the north/south divide through humour and startling moments of sincerity. Betts is often linked to Alan Ayckbourn, who appointed him as resident playwright of the Stephen Joseph Theatre, and there has been a considerable association with him in the lead up to Betts’ new play. But to too strongly examine Invincible in conjunction to Ayckbourn is to do it a disservice. It may be the faintly similar, but is able to stand strongly on its own as a hilarious and moving play, complete with strong performances from all members of the cast.

Invincible focuses primarily on Emily (Laura Howard) and Oliver (Darren Strange), the middle class couple to end all middle class couples. They have moved up north as a result of being hit by the recession, and invite round their new next-door neighbours Alan (Daniel Copeland) and Dawn (Samantha Seager), born and bred in the area and the chalk to Emily and Oliver’s cheese. Betts presents us with extreme portraits of north and south – Emily’s far-left hypocrisy and Alan’s love of footy and beer, for example, are extreme enough to create biting humour – but all four characters are recognisable in the real world, and are incredibly well developed, meaning they are far from stereotypes.

This is partially down to the strength of the acting. Using Betts’ canny recreation of regional and class idiolects, all four actors give impressive performances. The actors and their characters are at their best when bringing to life Betts’ monologues. As Emily, Howard excruciatingly digs herself into a hole with her extreme views; Copeland commands humour from the moment we meet his character by ironically talking too much about talking too much; once Dawn is given a voice, Seager gives an astonishing and moving performance; and Strange’s hysterical monologue about where he belongs is perfectly pitched to create hilarity. There’s a lot to enjoy in these varied performances. All four actors create different facets to their characters, meaning each character is well-rounded and never clear-cut, despite being so recognisable in portraying class.

The first half is greatly enjoyable, but director Ellie Jones never allows the play to rely on one tone of class-clash comedy. Tensions rise, and in the second half the play really shifts gear, toying with, at one point, a comedy of misunderstandings that is more Shakespeare than Ayckbourn. Sam Dowson’s set, with all the marks of a middle class home including eastern figure-heads and arty glass sculptures, is just as well-observed as Betts’ characters. The scene changes of the first half allow lighting to be used inventively, creating yet another type of comedy with ironic Charlie Chaplin-esque dancing and football celebrations, and help provide a refreshing contrast to the realism of the dialogue. Praise must go to Yasmin Dosanjh, who is credited for providing Alan’s frankly hilarious pictures of his cat, Vince, which in their reveal create a moment of joyous humour.

If I have to pick up on anything negative, perhaps I could complain that the technical aspects of the second half are far inferior to the strength of the light and sound of the first, or that the theme of Vince being named after HMS Invincible is not explored enough to warrant it worthy of the play’s title. But these are minor gripes in a great play that accurately and brilliantly chronicles the differences, similarities, highs, and lows of north and south, and creates both humour and pathos in doing so.

Invincible is playing at the St James Theatre until 9 August. For more information and tickets, see the St James Theatre website.