It’s a very clever play, and a witty one as well. But, at the end of it all, Julian Mitchell’s new play Family Business lacks one vital ingredient. It has no heart.

The succession of one-liners flows copiously. There are moments when it’s almost like an Oscar Wilde comedy transformed for the 21st century, with just a dash of Bernard Shaw polemics thrown in for good measure. We listen intently, but from the outside only.

Matthew Lloyd’s production is as effortlessly smooth as Mitchell’s writing and there’s a good set by Ruari Murchison which gives us the ground-floor of a barn conversion dominating (or perhaps hemmed in by) the neighbouring hills and valleys.

An excellent central performance comes from Gerard Murphy as William, a widower with a multi-million pound travel company recovering from a heart attack, who also has four grown-up children and a carer (apparently a left-over from his wife’s decline into Alzheimer’s disease). Ben Onwukwe matches him as Solomon, the softly-spoken, steel-cored survivor.

Then there are the four siblings. Jane has a financier husband (suffering from the recession), twin daughters (one with an expensive pony habit, the other heading for an equally expensive boarding-school) and an unbecoming greed as well as equally unpleasant prejudices.

Her brother Tom is trying to “go it alone” but his Chinese business-partner has disappeared off the edge of an unfinished motorway and the funds to finish a luxury holiday complex on a coral-reef atoll have been crushed with him. What's more, his Polynesian girl friend has recently given birth to their son.

Hugo is a born-again ecological warrior, at odds with his family in particular and the climate change-ignoring western world in general. And younger sister Kate? Kate is the dark horse in this stable, and she’s given real character by Anna O’Grady in a very well-paced portrayal.

You can also believe in Chris Kelham’s Tom and – in so far as his attitudinising allows – in Tom Berish’s Hugo. Partly because not all her words were as clear as they might have been, Tessa Churchard’s Jane is the least satisfactory person on stage. But I suspect that, just as we in the audience don’t like Jane very much, neither does the author.