The story sounds apocryphal, but it’s true. Alan Bennett, as shy and retiring as Mole in The Wind In The Willows, opened his curtains to find a Del Boy-style three-wheel van parked outside his London home.

If the sight caused a moment of satirical reflection, the playwright might have thought it was practical joke by his Camden neighbour and Beyond The Fringe protagonist Jonathan Miller.

But it wasn’t a jest. The Robin Reliant had an occupant, a lady of indeterminate age called Miss Shepherd. In her grungy cap and coat, she looked like a character out of a Samuel Becket play – End Game or Happy Days, perhaps.

Miss Shepherd, who might have been an ambulance driver during the war, and might have been a nun, moved on to Bennett’s drive, at his suggestion, and stayed put for more than 15 years until her solitary death in 1989.

She changed vans several times. Like a good Samaritan, the kindly Mr B connected Miss Shepherd to his mains electricity, doubtless at times wishing that he could do that for real. “One was rarely able to do her a good turn without some thoughts of strangulation,” he later said of his eccentric and sometimes troublesome neighbour.

She features in the first volume of his personal memoirs Writing Home. He later turned the relationship with The Lady In The Van into a play of that name; it opened in London in December 1999, with Maggie Smith as Miss Shepherd and Alan Bennett as himself.

Next month, a Hull Truck touring version parks at the Alhambra, with double Olivier Award winner Nichola McAuliffe as Miss Shepherd.

She says: “The play has been received extraordinarily warmly. It moves people on a lot of levels. A lot of people are carers of the elderly and there are two old ladies in this play, Miss Shepherd and Alan Bennett’s mother. Miss Shepherd is not a victim; she’s a kind of free spirit.

“I think what makes Alan Bennett one of the very few pre-eminent living playwrights in the English language is the connection he makes to life’s tiny tragedies, the minutiae of humanity he makes accessible but not patronising.

“He is not an intellectual snob. He connects with everyday human experience and makes it poetic.”

For those who know Miss Shepherd from Writing Home, the play has two Alan Bennetts, an ‘A’ and a ‘B’ you might say. One is external and one is internal. The internal one is the observer, the Bennett who observes himself observing. The external one, the Bennett who dealt with Miss Shepherd in everyday life, realised the fictional potential of this bizarre real-life relationship.

“It was symbiotic,” Nichola says, but she wouldn’t say whether the end of the play reflected the last act of Miss Shepherd’s life.

“The end is entirely in keeping with the nature of the play, which is to explore what it’s like to be a writer.

“Miss Shepherd is almost like Shylock: she is the fireworks, but she’s not the core. It’s about the dichotomy of what it’s like to be a writer: the schism between the internal and the external,” she adds. Alan Bennett always does well in Bradford. The stage versions of The Madness Of King George and The History Boys played to full houses at the Alhambra. Doubtless The Lady In The Van will have the same sort of reception.

Nichola McAuliffe was here before in the Royal Shakespeare production of Kiss Me Kate before it transferred to Stratford-on-Avon. Bradford was also the place where she says she sealed her relationship with her husband, newspaper crime writer Don Mackay.

“I have happy memories of West Yorkshire Police as well. I was at West Yorkshire Playhouse and I had to learn to use firearms, but there was nowhere to do it,” she says.

“A friend in the City of London Police said I should contact Keith Hellawell, who was Chief Constable of West Yorkshire at the time. He said, ‘We have a very nice firearms unit’. He took me out to it and we became huge chums.

“I remember Inspector Kevin Spencer – he was from Bradford. He brought a 52-seater coach of young people and police officers to see me in a play – Goliath, about inner-city riots – which got them talking to one another.

“It’s what theatre is all about. Fantastic!” she adds.

Nichola won Olivier Awards for playing the Baroness in Chitty Chitty Bang Bang at London’s Palladium, and for her role as the feisty but loving Kate in Kiss Me Kate.

On television she is probably best-known for her role as Sheila Sabatini in seven series of ITV’s Surgical Spirit, alongside Eccleshill actor Duncan Preston. And she appeared as Ken Barlow’s love interest Anita in Coronation Street.

* The Lady In The Van runs at the Alhambra from July 11 to 16. The box office number is (01274) 432000.