As head of England’s National Theatre for the past dozen years, Nicholas Hytner mounted stellar versions of such Shakespeare perennials as Hamlet, Othello, and Much Ado About Nothing, plus a number of operas on the side, and the odd musical or modern comedy.

Previously, as assistant director at the NT, he won accolades for his treatment of The Madness of George III, and veteran playwright Alan Bennett tasked him with directing its film adaptation (as The Madness of King George) in 1994. The same thing happened in 2006, with Bennett’s The History Boys. So it was no huge surprise when Hytner took time from his last year at the National to make The Lady in the Van, adapted by Bennett from his personal memoir of a cantankerous homeless woman who parked in his Camden Town driveway for 15 years.

The new movie, which opens here Friday (February 5), stars Maggie Smith as Mary Shepherd, the lady who wouldn’t leave—a part she had already played on stage.

“We shot at the actual location where Alan lived at the time,” says Hytner, on the line from his London office. He spent a couple of weeks a month before the shoot with Smith and Alex Jennings, a theatre veteran known for everything from indecisive Hamlet to the Decider, George W. Bush (in David Hare’s 2004 play, Stuff Happens). Here, Jennings has a dual role of sorts, as Alan Bennett the harried homeowner and as the deskbound writer, trying to judge how best to handle the intrusions.

“The work just kept changing,” recalls the Manchester-born director, knighted for his theatrical labours in 2010. “And it’s 15 years since we all did it last, as a play. We were coming at it fresh. Alan is always extraordinarily responsive, and we’ve worked together so often over the years, we have a very good shorthand.”

Hytner says the biggest difference now is how much Bennett put of himself into the story.

“Alan is extraordinarily well known and trusted over here, and I think he’s right to take the audience into his confidence. They really want to hear from him, and they identify with the sympathy he has with people who have somehow been left outside by society. He’s the great poet of those who feel that life has slipped them by. Nobody is so inside that they don’t occasionally feel that everyone else is getting on with their lives better than they are.”

In fact, this version pairs the decline of Miss Shepherd with Bennett’s perceived neglect of his own mother, up in Yorkshire.

“He’s extremely hard on himself,” Hytner asserts. “You’d never know from this screenplay that Alan has a brother who lived within a few miles of their mother, and that she was far from forgotten.”

Meanwhile, the director has been taking good care of his own life. He recently packed up shop at the National, the better to open the London Theatre Company at the new One Tower Bridge development, on the Thames.

“It will be 900 seats on the river,” he explains. “We will commission and produce original works with the kind of writers I’ve been working with over the past 12 years. Basically, I’m a theatre director who occasionally gets to make a movie, especially when there’s a play that feels like it could be turned into a film.” And, of course, when and if Alan Bennett calls.