“Each of us has two sides,” says Robert Louis Stevenson in Nigel Planer’s new play, and the imagery of Jekyll and Hyde percolates through this claustrophobic study of flawed, bedevilled creativity.

What kind of twilight awaits the artist, Planer wonders, and does our preparation for death colour everything that leads up to it?

The play is a diptych portraying the moribund agonies of two white men who have pickled themselves in the exoticism of the South Pacific.
The “long pig” of the title equates to the Polynesian word “paheka”, meaning “white man”.

First we see Robert Louis Stevenson, coughing himself to pieces in Samoa and bungling his relationships with his wife (a huskily emotional Amanda Boxer) and beautiful serving girl; then an impoverished Paul Gauguin in Tahiti, glugging back booze and obnoxious medicines.

Haunted by their ancestry and a sense of missed opportunity, the two are in their different ways “condemned to life”.

The more optimistic Stevenson hears in the tropical surf a “ceaseless requiem”: the bleaker Gauguin imagines the natives feasting on his corpse.

Sean Murray plays both in impressively full-bodied style. Yet his are the only rewarding roles. The other characters seem indistinct, and although Planer’s diligent research is obvious, its fruits have little sap.

There are some stylish musings, and Alex Marker’s neat design intensifies the sultry atmosphere, but the exposition is cumbrous, and the dialogue too often either strident or meandering, stretching credibility while failing to explore the more salient connections between Stevenson and Gauguin.
Until 1 August (0844 847 1652).