He looked dour and downcast. His black woolley hat was pulled down over his face. He was rather stooped under his black coat pulled tightly around him. Oooh, he has let himself go, we thought. And yes, he looked rather older than the fresh faced Gavin of Gavin and Stacey. An hour an half later, sitting in the audience at Windsor Theatre Royal, we looked at each other in sheer delight as he walked on stage and created the character of Raymond, the autistic savant. From his entrance on stage to the final curtain, what a transformation and what a heart-piercing performance. We realised he had just been getting into character. Written by Dan Gordon, this is a tremendous, powerful play with wonderfully written dialogue and masterful speeches (reminiscent of those by the great American playwrights, Arthur Miller and Edward Albee). Ed Speleers, who plays Charlie, Raymonds astute, car-dealer elder brother, holds the stage giving these lines with a passion which lifts up the audience in his embrace. Echoing the storyline of the 1988 film, the play opens with Charlies Los Angeles business on the blink and his secretary\/girlfriend, Susan (adroitly played by Elizabeth Carter) having to hold off his customers and creditors over the phone with sweet little lies. Then Susan takes the call telling them that Charlies father has died. He discovers that his dads huge fortune has been left not to him but to a brother he didnt know he had, severely autistic and living in an institution in Ohio. Charlie and Susan make the journey to Ohio where Charlie removes Raymond from his care home without leave aiming to take him back with him to Los Angeles. There is plenty of humour in this play which Horne manages to create by making us see things from Raymonds pithy point of view. It is a luminiscent performance. Between the matinee and the evening show, Horne and Speleers appeared for the press, beaming after yet another standing ovation from a packed house at Windsor Theatre Royal on a Thursday afternoon. Asked how he had done his research, Horne said: I have a severely autistic brother (Daniel) and I have lived with him for 39 years. Horne is approaching his 40th birthday and Daniel, who Mathew says has a developmental age of around four and cannot read or write, is now 42. Mathew says of his brother: He gets obsessed with things. He likes sixties rock and roll, Laurel and Hardy and 90s sitcoms. In the play, Raymond fixates on his television schedule as something that must be obeyed and knows the programme times off by heart. Some of my research is from living with him (Daniel). I am also an ambassador for Mencap. He explains how some autistic people find difficult things easy (like complicated maths or arithmetic) but (from a mainstream point of view) easy things difficult. Like travelling. I met a young man who if he goes through a door, for example into a public lavatory, he has to take a picture with his eyes so he can remember what is outside the door, once he has been through it. Otherwise, it will be a maze to him. He has worked out where he is on the autistic spectrum and that helped him have some control over his autism. Of Raymond, his character, Horne says: I have tried to make people feel comfortable with him and laugh with him rather than at him. He has an innate comic timing and a candidness that children have, a lack of self-awareness and of inhibition. Rain Man will be at Cambridge Arts Theatre from Monday, October 8 to Saturday, October 13. Shows at 7.45pm with Thursday and Saturday matinees 2.30pm. Tickets 01223 503333 or www.cambridgeartstheatre.com.