Miss Shepherd was a real person. She did indeed live in not just one but a whole succession of vans. Without doubt, her tenure as a resident in Alan Bennett’s garden spanned some fifteen years and she was, quite definitely, affected mentally by the events in her past – but exactly how much of the rest of her tale is true, and how much has been created by Bennett to make a great story, is not so clear.

In a stroke of pure theatrical genius, this piece opens with not one, but two portrayals of Bennett. Sean McKenzie, as Alan I and Paul Kemp as Alan 2 are dressed almost identically and narrate the tragic story of one of life’s outsiders. The first Alan is caring, considerate and somewhat intrigued by his new tenant while the second displays more irritation at her presence, but also sees an opportunity to harvest new material from her.

Alan 1 is mainly responsible for the interaction with the other characters in the piece, while Alan 2 is more of an observer, an almost benign figure. Both portray Bennett’s look, mannerisms and speech, using that distinctive Yorkshire accent, perfectly. They deliver the dry witty lines with comic precision and, within the first few sentences, have the audience gripped.

The dual storylines of Miss Shepherd’s occupation of the garden and the slow decent into dementia of Bennett’s own mother (Fenella Norman) pull firmly at the heartstrings but, as with so many of his works, the comic observations come thick and fast and ensure that the audience stays upbeat throughout.

The Social Worker, an amalgamation of so many well-intentioned professionals, is quite brilliantly portrayed by Sophie Robinson. Determined to do all she can to assist, she has no idea that she is being used simply to supply a new walking stick and wheelchair and is drawn so far in that she even makes a contribution of her own second-hand clothes.

Sarah Esdaile’s direction is, at times, a trifle slow, but that's a minor point in a production with so many pluses. The set is dramatic, with a high, concave, black wall illustrating perfectly that all parties in the tale are somewhat trapped. Add to that an array of dilapidated vans of various shapes and sizes, and the feeling of claustrophobic hopelessness is palpable.

Nichola McAuliffe proves exactly why she is one of our greatest character actresses with a performance that is both comic and poignant. Dressed in a number of layers of filthy clothes, with skin that is equally dirty, she looks every inch the vagrant. Her personality leaps from being vulnerable, scared and alone to angry, argumentative and stroppy with frightening regularity. Her appearance in Act Two is as shocking as it is sad but, with usual Bennett flair, she gets to have the last laugh.

The piece could either be a sad indictment of the way some people are marginalised by society or just as easily be comic reflections on the life of a great British eccentric. Either way, it’s a great production.