Playwright Alan Bennett said he has no plans to retire as long as people continue to have an appetite for his works, at the premiere of his new film on Tuesday evening.

The 81-year-old wrote the screenplay to The Lady In The Van, adapted from his diaries and based on the real life story of Miss Mary Shepherd, an eccentric woman who lived in a battered yellow van on his driveway for 15 years.

He said: “I’m not particularly proud that I’m so slow but I’m grateful people still want to see my stuff and they probably tolerate me really.”

Alan Bennett
(Ian West/PA)

The film is the big-screen adaptation of the original 1999 play, starring Dame Maggie Smith as Miss Shepherd.

The 80-year-old actress, who was nominated for best actress at the 2000 Olivier Awards, reprised the role in the 2009 Radio 4 adaptation before the movie.

Alan said the role was written for Dame Maggie: “I’m glad to see it made permanent on film. A stage production if you haven’t seen it, that’s it, but on screen it’s there for good.

“Also you get in so close on screen you can see what a wonderful actress Dame Maggie is.”

Maggie Smith
(Joel Ryan/AP/PA)

The playwright, who is portrayed on screen by Alex Jennings, said the story continues to be as poignant today even after Miss Shepherd’s death.

“It’s not revisiting in the sense it never really left me. Even today if I hear the front door go, I think it’s Miss Shepherd. It’s ingrained so much into my life.”

But he said the real Miss Shepherd would have issues with the film.

He explained: “She would probably think she deserves a bigger part because she had a very exaggerated sense of her own importance. She would also want to put over her political and religious views which were very pronounced.”

Alex Jennings, Maggie Smith and Alan Bennett
(Ian West/PA)

The film marks the second collaboration between Alan and director Nicholas Hytner since The History Boys in 2006.

The filmmaker said: “We first did the play in 1999 and neither of us could quite remember why we didn’t make the film then.

“I’m very glad we did it now because we’ve had time to think about it and Maggie is even more like the lady in the van now the she was 15 years ago.”

Maggie Smith and Alan Bennett
(Ian West/PA)

Earlier, Dame Maggie revealed she disliked staying in the van for the duration of the seven-week-long shoot.

She said: “It was not very easy being constricted in a van. There is no way you could live in a van, surely not for that length of time. The rest of the cast were in luxury in a real house.”

Nicholas added:”The van was a nightmare for Dame Maggie, hurling herself in and out of that van.

“The energy that she brings is extraordinary and I used to feel really guilty asking for a second or third take because she’s getting on.

“She’s 80 and she’s having to hurl herself into the van, run up and down the hill, chase children. The physical energy she brought was quite frightening to watch sometimes. She was pretty brave.”

The Lady In The Van opens in cinemas on November 13.