Surrealism sings at the Soho, director Steve Marmion following Anthony Neilson’s Realism with a bizarre office play by Ed Harris that provides an engagingly original hour or so of theatre before treading water in the later stages. But this is a distinctive and pungent new play.

It’s also refreshingly weird without being irritating. Office play classics such as Vaclav Havel’s The Memorandum or Michael Frayn’s Alphabetical Order proffer metaphorical theatrics of political and personal application; Mongrel Island is just out and out peculiar, with night-time conversations sprouting between the filing cabinets, not to mention a giant prawn called Jimmy.

Marmion’s production is also very well designed by Hayley Grindle – her office, with an upstage inner sanctum for the boss, manages to be cluttered and ordinary as well as gleaming and surprising – and very well acted, primarily by Robyn Addison as the new girl, Marie, and Shane Zaza as an unlikely Asian Elvis with a passion for bicycles.

Marie, who is settling into the dry routine of transferring data into a new computer system, embarks on an adventure, like Alice in Wonderland, into a parallel universe of fantasies and arguments which also involve Simon Kunz’s embittered Only Joe and Golda Rosheuvel’s status-flaunting Honey, the office manager, who is wonderfully compromised in an imaginary (or is that real?) rough sex session with Only Joe at dead of night.

Marie finds more of an ally in the little cleaning lady, Pippop (Joanna Holden), whom Harris suggests in his script could also be played by a puppet. Holden makes of her a malevolent little Miss Havisham of the mop and bucket, while Only Joe unwittingly unleashes an avalanche of pink ballet shows. This follows the surprise discovery of envelope-fuls of tulip petals and a stash of wire dentures and bra supports.

The actors meet the oddities full on, with straight bats, so that Marie’s voyage of discovery is every bit as touching as Only Joe’s embattled philosophising and Elvis’s related encounter with Jimmy the Prawn underneath the railway bridge. I can’t imagine what Ed Harris will write next, but I’m looking forward to it already.