One time top actor of the small screen Gerald Harper comes to Oxford to star in an Agatha Christie play, writes NICK UTECHIN

Anyone who knows their Agatha Christie will remember that this is not the original title of the 1939 book. That was Ten Little Niggers, watered down for publication in the US a year later to Ten Little Indians. That, in turn and in time, became almost as difficult and so And Then There Were None settled in as the name of the book and the play.

Christie herself did the theatrical adaptation, working on it intermittently for two years. In the original, all ten people on the mysterious island die; so the ending had to be changed. In her autobiography (so it can't be giving too much away in advance), Christie wrote: "I must make two of the characters innocent, to be reunited at the end and come safe out of the ordeal." Even when she had completed work, there were at first no takers for producing it - everyone believed it impossible to make it work successfully on the stage. It eventually premiered in 1943.

This production is staged by the Agatha Christie Theatre Company, which has had exclusive rights to tour the writer's original stage plays in the UK since 2006, and is licensed to the impresario Bill Kenwright by Agatha Christie Ltd, run by the author's grandson Mathew Prichard. He told me what needs to be done to protect even so famous a writer.

"Over the years we have refused far more ideas for development of various kinds than we've accepted. In the modern world, there is almost no property that survives or thrives on its own merit entirely - it has to have encouragement or protection from its owners. Kenwright produced the most impressive ideas both from a business and artistic perspective."

I think the cast is going to help, too. Anyone who remembers Dixon of Dock Green will recall the young detective Andy Crawford (Peter Byrne), and those of the same age who bought the hit pop single Venus in Blue Jeans will know the name of its singer immediately (Mark Wynter, who transformed himself into an actor). But even these two veterans are upstaged by the play's lead, Gerald Harper.

Exactly 42 years ago this week, Harper leapt into the public's consciousness as Adam Adamant on television, the frozen Victorian gentleman-adventurer who defrosts in the Swinging Sixties. Two weeks ago, he spoke to me from his dressing room in Peterborough.

"I was sitting in my house in Spain, not wanting to work, when the telephone went. My agent said: 'D'you want to do And Then There Were None?" I shouted: 'Yes!'. I did it 60 years ago at school and adored it. Five years later I did it in rep in Sheerness. It always takes me back to my youth."

Harper plays Justice Lawrence Wargrave, which means, I presumed, that he is the detective figure.

"Well, let's say that because he's a judge and has a very sharp mind, he does tend to take the lead in what happens. This is the only Christie I've done, but it seems to me she wrote just as well for the stage as the page. She draws the most remarkably interesting characters, characters that get the audience on to their side."

Mathew Prichard also gave me a personal insight into his grandmother's skills as a playwright.

"She came to the theatre seriously comparatively late in life, but loved and was fascinated by it, and the professional challenge of creating a whodunit that fooled a live audience - a very different task from a book. But she didn't like the inevitable razzmatazz of the theatre much."

Throughout his career, Gerald Harper has always preferred stage work to small or large screen: his huge success in two series of Adam Adamant and several on ITV as the eponymous Hadleigh provided the means to a specifically mapped-out end.

"I only did TV to make me famous so that I could get leading stage roles. If you think of it, each episode of those shows was a straight commercial for me. In my twenties, I was in a play with Alec Guinness, and there was his name in flowers and there was mine at the bottom. And I read a book called Management By Objectives and set myself certain objectives."

The main one was to get a new agent - Harper told him to find a television role for him and turn down theatrical engagements. It worked, and Adam Adamant - the idea of whom still makes middle-aged women weak at the knees - came along.

"It was enormous fun and I have enormous affection for it. It was like weekly rep with a better dressing room. We made the first 13 in 13 weeks, including rehearsal time. But after that, and after Hadleigh, I remember walking down Shaftsbury Avenue with three play scripts, all casting me in the lead."

And then there were no more objectives, and Gerald Harper has been in work ever since - when he chooses to take a break from his Spanish home and stop fishing for a while.

And Then There Were None is at the Oxford Playhouse from Monday until July 5. Call the box office on 01865 305305.