When she sees similarly dressed women parading en masse in dog-walking clubs, running clubs or straggling lines of power walkers, novelist Gill Hornby reckons they have a peculiarly female leader-following instinct that she never acquired.

“I can’t take vast groups of women. For me it’s four women max, in a group of undiluted females, more than that and I’m heading for the door. The people who thrive in large groups of women have instinctive skill and dedication to being part of the group.”

As she speaks, Hornby is tending her quietly labouring cat Tabitha, the cat’s womb full of kittens competing to be the first to get oxygen. Writers living together can be like that, as they compete for air and sustenance.

Hornby, though, seems as patient as Tabitha: the writer waited until the age of 54 to produce her first novel after years of being a mostly full-time mother to four children. She has been married, for 25 years, to Robert Harris, best-selling novelist, notably of Fatherland (1992). Her brother is writer Nick Hornby, author of Fever Pitch, High Fidelity and About a Boy.

“I’m a late developer. I feel about 23. It feels fantastic, admittedly, to be doing something completely different in your 50s. I think the key to ageing is to do new things. It’s quite refreshing and it’s lucky because writing is something you can continue doing into your elder years,” she says.

Whether family connections helped her to get published is an obvious question and she’s prepared for it with several answers.

It’s unusual to have three successful writers in one family, but why not, she argues. And if your novel is being published as a favour to someone, you don’t find your book in a six-way international auction that reaped a six-figure deal, like she did.

"It was extremely unexpected," she says. She had the idea for her Mumsnet meets Mean Girls novel, The Hive, set around the school gates, "years ago" and it does seem more Noughties than recession-pressed 2013.

She began writing it in 2010, with her agent insisting she finish the book before pitching it, so that Hornby had “no idea” that it would receive such a welcome.

No one helped her write it. Only when she showed him the final draft did Harris suggest she add seasonal weather to the school year, to help differentiate time.

He probably should have shown her a way to differentiate the female characters as well, because they do muddle together and become difficult to care about, even apart from the fact that several of them are awful people, suffering from contagious, sudden onset blondeness as they compete for status.

To be published is clearly a thrill for Hornby, but it hasn't been a smooth journey. Two life-changing decisions came from rejection. The first was when, after a successful career in TV (she met Harris while working on Newsnight), she moved to BSkyB and was fired, along with many colleagues, when she happened to be on maternity leave with her first child.

“It was a crisis that changed my life. Then, after my daughter was born, I realised: ‘What a relief never to have to go back.’ I never thought I’d be one of those who don’t continue to work, but I was bowled over by having children and very lucky and happy to be able to do it full-time. We could never have afforded it before Robert’s success in 1992.”

Rejection turned to success as she reared her family in the magnificent former vicarage in Kintbury, Berkshire, which was once visited by Jane Austen, and Harris was photographed by Annie Leibovitz, in the impressive book-lined study, for Vanity Fair. Ballymaloe was the family's annual holiday destination for years, a far cry from the council estate on which her husband was reared. Despite a privileged lifestyle, she was deeply affected by her second big career rejection, which came in 2010 when the Daily Telegraph dropped an opinion column she had been writing for some years. With her children growing older (they're now aged 12, 16, 21 and 22) she decided it was time to write the book. "My husband has always said 'you have to write a novel', so I thought, 'I'll have a go'," she says.

Hornby doesn’t suffer the bouts of depression her brother Nick has written about. She felt post-natal euphoria rather than depression as a new mother and is sailing through menopause symptom-free. She keeps repeating how lucky she is to have such a great life.

The Hive owes a lot to Queen Bees and Wannabes, Rosalind Wiseman's book about the social structure many females are drawn to, a source that Harris credits in the acknowledgements.

The queen bee in The Hive is rather obviously named Bea, and the protagonist, Rachel, has just been dumped by her in favour of more malleable slaves. Her husband leaves her too.

Long and happy marriages in The Hive are scarce – in contrast to Hornby's own marriage to "a patient man who puts up with me" – with the only happy wife in the novel coming in the form of Georgie, an earth mother type who has given up a career for messy family living.

Hornby says Georgie is most like her, although her own childhood was rather different.

Her parents both left school at 16 and divorced when she was a child. Her mother worked as a secretary – “there was no silver spoon” – while her father went to the US and became a successful executive.

“He was supportive financially but we did not see much of him. We were very much a single-parent family,” she says.

As a schoolgirl, student and professional woman, Hornby was disaffected by cliques. “I am an outsider and could never have been a queen bee in a million years. It’s pretty hard work being popular at that level,” she says.

When her first child started school, she once again found herself observing a queen bee situation and thought: “Here we go again.”

The Hive satirises the ladies who lunch competitively, the incessant school fund-raising, the car-boot sales and table quizzes. It has some comic moments, such as when the mother of a "weird" child is devastated when a psychological assessment reveals that her son is neither "special" nor "gifted", merely average and strange. (None of her own children inspired this, she adds.)

Her portrait of womankind as intrinsically bitchy, disloyal and insecure is angry and deprecating. Was she seeking revenge on anyone?

“No one specific. I have known a lot of these queen bees, some are very benign women who don’t get spoiled and make the world go round. We need them.”

She’s enjoyed the advantages of being an outsider, which brings better quality friendships, she believes.

“By refusing to be in a group, you end up with friends who are also refusing to be in a group. You do end up with longer lasting, loyal friendships,” she says.

As Georgie realises in the novel, after she is ejected from the hive: “Something else, other, had grown out of that. There was now a group – a tight, taut network of people who care about her and her children and would never stop.”

In a film version, Hornby would love to see Bea played by Gwyneth Paltrow, whose blogs on family life and healthy living are followed by millions, and Georgie played by Tina Fey.

Clearly, she sees the film as a satirical comedy, which doesn’t quite come across in the book. The kittens, meanwhile, have all gone to lovely homes.