Meeting Charlotte Philby feels a little like being a secret agent liaising with their handler. When I arrive at the restaurant by London Bridge she materialises as if she’s been casing the joint for a while and has watched me arrive. We sit on stools at a high-top table, Philby facing into the room. It’s almost as if she’s keeping an eye on the exits.

This is all a product of my imagination, of course. The prospect of interviewing the granddaughter of Kim Philby, the most notorious double agent of the 20th century, will do that to a fan of spy fiction. We met briefly once before at a book launch. On that occasion she was utterly charming. This time there’s a steely edge as well.

Philby has just published her fifth novel, The End of Summer, and this one is a change of direction, a clever commercial thriller with three generations of women in the leading roles. The star of the show is Judy, a con artist who falls for her mark and may or may not be leaving a trail of bodies in her wake as her past catches up with her. Her daughter, the more conventional Francesca, tries to find out while dealing with her daughter Lily, another live wire. “These traits run through families,” Philby says. “They skip a generation.”

There is much in this book you would imagine the granddaughter of a spy to be expert on —uncovering family secrets, subterfuge and betrayal. “Judy is everything that I would like to be, but I’m held back by the side of me that’s more like Francesca,” she says. “Judy’s less bothered about what people think about her.”

What people think of Charlotte Philby is shaped by her surname and it has helped and hindered her. Her first three books were not spy thrillers, but novels with espionage themes. In her previous book, Edith and Kim, she confronted her family story with a novel about her grandfather and Edith Tudor-Hart, the woman who introduced him to his Soviet handler. She’s writing the film adaptation, but “I’ve made it far more about Edith and I’m changing the title”.

Kim died in 1988 when she was five, but she visited him twice a year in Moscow as an infant. “I have these sort of memories that I think are memories rather than from photos or family folklore. I remember being in Moscow in the flat and there being rifles on the wall and my dad and my grandfather playing chess at the table. And it was all very sort of convivial and exciting.”

Charlotte grew up in north London, where she attended the fee-paying Queen’s College, Harley Street, and the comprehensive Camden School for Girls, and read English literature and media studies at the University of Sussex. She returned to Moscow with her husband ten years ago and found Kim’s flat and his widow, Rufina. “There was a little framed photo of me and him on the side next to the sofa where we used to sit.”

What she shares with Kim is the ability to juggle many identities. Charlotte, 41, was a journalist for 20 years and is a mother of three who takes herself to her “posh shed” at the bottom of the garden (built by her husband, Barney, a designer) and writes full-time until 2.30pm when she goes to pick up the kids — one girl and two boys aged between 8 and 13.

She also helps to run an art gallery in Bristol, where she lives. She has a “true life story of spies for children” in the works. And in February 2025 Baskerville, the imprint that publishes Mick Herron of Slow Horses fame, will launch the first of Philby’s new series of detective thrillers, Dirty Money.

Charlotte has, she says “hyper focus” for writing while “other parts of my life are highly chaotic — my house is a complete mess. But I just love writing. It’s a compulsion. I’m fascinated with women leading double lives. I feel like I’m living multiple lives.” Judy is the same. “She can be reckless, but she has a moral code and she is wedded to her family. When we look at spies, con artists, criminals, often we look at the men and their decision making is quite straightforward. The moment we have a woman who is a mother, you’re suddenly balancing so many different commitments.”

Francesca’s character is informed a little by Charlotte’s experience of watching her father deal with his father’s notoriety. Charlotte’s father was a photographer for The Sunday Times during the Vietnam war and took the pictures of Kim Philby posing behind a tree after his defection. “He was proud of Kim in the sense that he had the courage of his conviction. What happens when your parent is a spy? And what happens when you suddenly realise that every decision that they have made has been on the basis of something that you can never understand and will never understand.”

In The End of Summer “Francesca is trying to understand where Judy is coming from. The decisions that you make when you’re young, and you make those decisions in one life, and then suddenly you find yourself in another life, and you can’t predict how you will have felt when you get there.”

I assume Judy is a female version of Kim. And this is where it gets really interesting because it may just be that Kim Philby is not even Charlotte’s most interesting grandparent. “Actually it’s my maternal grandmother, Joan, who was this extraordinary, audacious character,” Charlotte says. “She had three children, but her eldest, my mum, was 20 years older than the youngest. And when my grandmother died I inherited all her stories. She was a voracious writer.

“When she was approaching her 50th birthday, she said, ‘The prospect of all those ghastly cameras and candles, I just knew I had to get out of there.’ So she booked herself on a boat to Africa, turned up at my mum’s door with her five-year-old and said, ‘Could you look after him for six months?’ And buggered off to Africa.

“She’s one that I am most inspired by. She nearly married an Egyptian whose parents ran a famous antique bookshop in Soho. At the last minute she said, ‘I can’t do this.’ And she married my grandfather, who was a bank manager. She was looking for that security that she never had.”

As we talk it becomes clear that Charlotte wants the security of a reputation based on her work, not her name. “I have been labelled as a spy writer, which doesn’t feel to me like who I am or what I am. I understand that having that name attracts a degree of attention, which is useful and I’ve certainly benefited from that, but I have never written a traditional Cold War novel. I have no interest in doing that.

“I don’t regret writing spy novels, if that’s what they are, but I wish I’d established myself in my own right first. When you spend so long being told, ‘This is what’s interesting about you,’ as I have, you start to believe it. Writing The End of Summer was a way of breaking free, of reclaiming a part of myself and feeling unshackled.”

It’s a cracking good read, pacey and packed with psychological suspense. The best twist of the lot was this: I arrived to meet Charlotte Philby, granddaughter of a spy, and left having interviewed Charlotte Philby, one of the rising stars of British thriller writing.

THE END OF SUMMER is published by Borough Press. Buy here