Taking The Casual Vacancy from the page to the screen

The Casual Vacancy is set in the fictional Cotswolds village of Pagford

The writer and director of the BBC One dramatisation of The Casual Vacancy, which starts on Sunday, reveal how they adapted JK Rowling's first "adult" novel for the small screen.

Eyebrows were raised in 2012 when JK Rowling followed her blockbuster Harry Potter series with a dark contemporary novel full of adult themes and language.

Yet that did not stop The Casual Vacancy - a study of back-stabbing and skulduggery, all set in a seemingly idyllic English village - from becoming a global best-seller.

Now Rowling's 500-page doorstopper has come to the small screen, with a large ensemble cast headed by Albus Dumbledore himself, Sir Michael Gambon.

According to its director Jonny Campbell, however, the authorship of the material was something best put to one side.

"I tried to ignore the JK Rowling factor [while deciding to take on the project] and concentrate on it as a story," says Campbell, whose previous work for the corporation includes 2011's Eric & Ernie.

"What appealed to me is that JK had this idea to write a novel with 19th Century sensibilities in a contemporary setting."

Sir Michael Gambon plays Howard Mollison, chair of the parish council

Comparisons to Dickens were made when The Casual Vacancy was published, including by the BBC's arts editor Will Gompertz.

It seems fitting, therefore, that the adaptation be crafted by someone with experience in this area: Sarah Phelps, whose previous BBC commissions include adaptations of Oliver Twist and Great Expectations.

"I've adapted dead writers before, which is great because they can't come and bother you," jokes the former EastEnders writer.

"But Jo was brilliant about giving me the freedom I needed. She's used to the process of adaptation from having the [Harry Potter] films done, so she understands."

Rowling for her part has been effusive in her praise for Phelps' efforts. "Sarah has done a great job and I am delighted with how it has turned out," she said in a statement.

Readers of the original, however, will notice some deviations from the original text, especially when it comes to the central point of dispute for the residents of the picturesque hamlet of Pagford.

"In the book the dispute is over a boundary line, which is a difficult thing to put into a TV drama," says Phelps.

Julia McKenzie co-stars as Howard's calculating and ambitious wife

So the decision was made to create a rundown community centre whose philanthropic aims - to better the lives of Pagford's council estate residents - are anathema to its wealthier, snobbish denizens.

"There used to be an awareness that wealth was there to spread out," says Phelps, citing the example of 19th Century entrepreneur George Peabody and his quest to provide affordable housing in central London.

"I thought it would be a good way of anchoring the argument about where we were then and how things have changed."

There is also a heightened presence for Barry Fairbrother, the local parish councillor whose death at the beginning of the book creates the "casual vacancy" of the title.

"Barry dies on page three in the novel," says Campbell. "But Sarah cleverly found a device to let us get to know him a bit and show his relationships with other characters without relying on flashbacks."

"One of the challenges we faced in the first episode was to introduce all the characters without confusing people," the director continues.

Painswick in Gloucestershire doubled for Pagford in some scenes

"The novel has a lot of characters who have a lot of interior monologues, which is not something you can do so easily in an adaptation."

Fortunately, Campbell could draw on the likes of Keeley Hawes, Julia McKenzie, Emilia Fox and Simon McBurney to flesh out Rowling's large and colourful ensemble.

"It was nice playing against type," McKenzie says of her character Shirley Mollison, the calculating and ambitious wife of Gambon's parish council chairman Howard.

"I'm normally offered something with a duster in my hand, so it was very nice to be offered it."

The Casual Vacancy begins on BBC One on 15 February.