On paper it looks like a good match: satirists united across the decades. Ian Hislop, editor of Private Eye, and his longtime collaborator Nick Newman (they first worked together on Spitting Image scripts) have dramatised the acid-sharp The Autobiography of a Cad by Scottish writer AG Macdonell (their fifth play for the small but perfectly formed Watermill theatre). What could possibly go wrong?

The novel, published in 1938, covers the life of Edward Fox-Ingleby across roughly the first 26 years of the last century: his landed background, entitled youth at Eton and Oxford, debauched years as a rake about town, profiteering during the first world war, entry into politics, marriage, adultery, double dealings – think Evelyn Waugh but without that author’s sunny view of humanity. Macdonell’s cad presents himself to the reader as a gentleman, covering despicable actions with self-serving, pseudo-altruistic justifications. He typifies the worst kind of landowner, capitalist, politician, developer and misogynist, a composite character revealing the spectrum of corruption across society in his time – and all times.

Where the adaptation does indeed go wrong is in trying to cut and paste the picaresque, first-person narrative into a linear development that focuses the antihero into the character of a dodgy politician. The full scope of Fox-Ingleby’s malevolence is lost; he is reduced to a conceited, blustering bounder.

Hislop and Newman set themselves a tough task, made harder by budget constraints, limiting their cast to three – but what a trio. James Mack revels in the melodramatic exaggeratedness of the title role. Rhiannon Neads and Mitesh Soni kaleidoscope through 20-plus other roles – each a distinctive gem. A playful spirit characterises every element of director Paul Hart’s well-crafted production. Scene by scene, the script delivers witty, even laugh-aloud moments, but they’re like the stutters of an engine that fails to spark; the whole does not hold.