Of course I know about Ian Rankin. Everyone does. Of course I’ve heard about Inspector John Rebus of the Glasgow Police. Absolutely. But… you can guess, can’t you, gentle reader, I’ve never read any of his books or encountered Rebus in any format until last Monday evening in the intimate charm of the Royal Theatre in Northampton, where Rebus: Long Shadows has come for a week as part of its UK tour.

I wondered whether I should find out a bit about this famous Scottish cop in advance of the show – but in the end I decided to let the play talk for itself, so Mrs Chrisparkle and I both went into it with absolutely no preconceptions. It’s not an adaptation of an existing novel, but a new work, taken from a story that Rankin devised for the play but then passed to, and was written specifically as a play by, Rona Munro, responsible for those fascinating James Plays a couple of years ago.

Late one night, Ex-Detective Inspector Rebus chances upon a young woman on his staircase, who turns out to be the daughter of a woman murdered years ago. The local police messed up the investigation so that her murderer was never caught. Although Rebus is no longer on active duty, he decides to follow up a few loose ends to try to solve the case. At the same time, Rebus’ protégé DS Siobhan Clarke is involved with another case, where another young woman was murdered in the past, and also not solved. The two investigations end up converging, with all roads leading to Rebus’ nemesis, Big Ger Cafferty.

Ti Green, whose design for the recent production of Touching the Void was so dynamic and inventive, has here created an ultra-grey and depressing world, dominated by a grim set of steps in the centre of the stage, and a dour flat furnished with only grey office filing cabinets and featureless walls. If the intent was to express a minimalist, depressing environment, she certainly achieves that! Occasional touches of the outside world appear, such as inside the traditional local pub, and the splendour of Cafferty’s drinks trolley. Robin Lefevre, who’s directed more plays than I’ve had hot dinners, has concentrated on making the character of Rebus centre stage throughout, and Charles Lawson’s performance is pretty impressive. He’s an honest, thoughtful, diligent and, at heart, a kind man, but with a rough exterior and a gruff voice that made Mrs C think she had been transported to an old episode of Taggart. His ungainly stance and quirky character make him intriguing to watch – although I absolutely hated that final tableau right at the end of the play; the light illuminating Rebus’ quizzical expression as he perched atop the staircase crossed hero-worship with pure hokum.

John Stahl is superb as Cafferty, a menacing but privileged presence, dispensing glasses of £650 per bottle claret like it was Tesco Everyday Value; a Glaswegian underworld Vinnie Jones with the keys to Fortnums wine cellar. Mr Stahl really impresses with the character’s sly-and-shiftiness, and clever manipulation of all situations to his own benefit. I also very much enjoyed Dani Heron and Eleanor House’s virtual double act as the ghosts of the two dead girls, pressurising Rebus’ conscience to put right the wrongs of the past. Neil McKinven has the arduous task of taking on five roles, and successfully gives each one their own characteristics so we’re never confused as to who he’s taking on at any one time.

But it’s with Cathy Tyson that this production seems to go a little awry. Not with Ms Tyson herself, I should say; she gives a strong, clear, determined performance, just as you’d expect from someone of her experience and skill. However, if she’s Rebus’ protégé, she never shows it; there’s no sense of respect or admiration for him. And there’s no light and shade in her reading of the role; she seems set on 6th gear turbo drive throughout so you don’t get a sense of her character, she’s just a cop doing a cop’s job. I couldn’t decide whether that was a fault of the writer, the actor or the director. But somehow it just didn’t quite feel right.

Although I had a few reservations – including a very unconvincing stage fight – it’s still an entertaining story and a diverting way of spending an evening. We found ourselves enjoying it despite itself, if you get my drift. It hasn’t piqued my curiosity to plunder Rankin’s back catalogue though – and I’d rather hoped it would. After its time in Northampton, the tour continues to Aberdeen and Guildford.