JK Rowling's first novel for adults, The Casual Vacancy, draws on her own experience of living on the margins of society and satirises a political landscape in which the poor are regularly cast "as this homogeneous mash, like porridge", according to a rare interview in the Guardian's Weekend magazine.

The idea for the novel, her first since the 2007 publication of the final volume in the Harry Potter series that made her a global household name and the world's first author to become a billionaire solely through her writing, came to her on an aeroplane. "I thought: local election! And I just knew. I had that totally physical response you get to an idea that you know will work. It's a rush of adrenaline, it's chemical. I had it with Harry Potter and I had it with this."

Set in the fictional West Country village of Pagford, which bears a passing resemblance to Rowling's own childhood home in the Forest of Dean, and telling the story of a parish election triggered by the death of councillor Barry Fairbrother, The Casual Vacancy investigates the agendas and infighting that fuel local politics, and the class divisions that rive even the most picturesque English communities.

The election ultimately turns on the fate of Pagford's grotty council estate, the Fields, embodied in The Casual Vacancy by the wretched, wrung-out Weedon family: mother Terri, struggling to kick her drug addiction, three-year-old son Robbie, under threat of social care, and teenage daughter Krystal.

"So many people, certainly people who sit around the cabinet table, say: 'Well, it worked for me' or 'This is how my father managed it'," Rowling said. "The idea that other people might have had such a different life experience that their choices and beliefs and behaviours would be completely different … seems to escape a lot of otherwise intelligent people. The poor are discussed as this homogeneous mash, like porridge … They talk about feckless teenage mothers looking for a council flat. Well, how tragic is it that that's what someone regards as the height of security or safety?"

Rowling's own experience of poverty – writing the first Harry Potter novel in Edinburgh cafes while she and her daughter survived on state benefits – and her emergence from it are now the stuff of literary legend.

The Casual Vacancy has featured on the bestseller list since the announcement of publication "on the strength of pre-orders alone", according to a spokesman.

Jon Howells of Waterstones, meanwhile, said of the bookseller's staff, who will take delivery of the closely guarded books on Wednesday, that "everyone's very excited and curious".

Nobody, he said, was treating the book "as if it were another Harry Potter" but, "that said, there is a little bit of that inherent craziness still there. It's an 8am embargo, and all our shops near as dammit will be open at 8am – they're usually open at 9am. I don't think it will match the first-day sales of a million-plus for the last Harry Potter, but we all expect it will be the biggest hardback novel of the year. There is competition out there, but this is JK Rowling."

沪江快讯：JK罗琳的首部成人小说《临时空缺》（The Casual Vacancy）即将于周三上市，故事发生地设在英国西南郡一个虚拟的小镇佩格弗德（Pagford），这个小镇看似充满诗情画意，但在其平静之下却隐藏着激烈的争斗。情节以一位名叫巴里·费尔韦瑟（Barry Fairbrother）男子的突然死亡震动整个城镇作为开篇，人们为争夺他在当地议会中的席位引发了一场“小镇史上最大的战争”。在该书中，罗琳也带入了自己曾身处社会边缘的经历，虽然该书目前尚未开售，但已登上英国亚马逊网站上最被看好的预售小说榜单。