When Kamin Mohammadi's family fled their home in Ahvaz during the 1979 Iranian revolution, foremost in the nine-year-old girl's mind was the fate of her pet lamb, Baboo. Having indicated they were only going to Tehran - the family put it about that they were leaving only for a short holiday, to avoid unwanted attention - Kamin begged her mother to let her return to their home one last time, to say goodbye. But the danger was too great, and she was refused.
A few days later, Kamin learnt that Baboo had been eaten for lunch by relatives. A day or two after that, the Mohammadi family were on a flight bound for London: Kamin would not set foot in Iran again for 17 years.
"These are the sorts of things that are important when you're a child," says Mohammadi, smiling. "I didn't really understand the revolution, and everything that was going on. But I was heartbroken about poor Baboo.
"Really, it's only when I started to write this book that I began fully to get to grips with what had happened to us. That was what was hardest about writing this book: reliving the trauma. There was a deep wound there that had not been addressed."
The book in question is The Cypress Tree, Mohammadi's acutely observed, sad, funny memoir of an Iranian childhood interrupted by the events of 1979. Here, then, are blissful, innocent days spent at the family's home in Ahvaz, where her father was a director of the National Iranian Oil Company, followed by sudden displacement to England, and years in London during which Kamin pushed away her Iranian background before a return to Tehran in 1996 saw her admit, finally, that hers was a story worth telling, and treasuring.
It seems fitting, somehow, that we meet only minutes away from the Conde Nast headquarters where Mohammadi has forged a career as a magazine editor. The location seems perched between two eras of her life: the London years, and then the reclamation of Iran.
It was in 1996, when she went back to Tehran, that the author knew she must tell her family's story.
"I wanted to tell people about my family, who were such amazing characters," she said. "At first I tried it as fiction, but I saw it wasn't going to work that way: it had to be a memoir. Most of all, the desire to write the book was just a version of my desire to communicate about all this stuff that I'd pushed away for so long: leaving Iran, everything."
If Mohammadi distanced herself from her Iranian background for years, it was an understandable reaction to the culture shock she must have felt upon touchdown at Heathrow airport in 1979. Before the revolution, hers had been an affluent, middle-class Iranian childhood spent between Tehran and Ahvaz, where the family lived in a compound for oil company employees: there were poppies growing on the lawn, and a date palm in the sprawling garden. But then, via the inexplicable logic that governed the revolution, Bagher Mohammadi's position with the company made him a target for arrest, so all of that was hastily exchanged for a flat in the central London district of Kensington and, for Kamin, a boarding school in the Suffolk countryside to the north-east of the capital.
Mohammadi is touching and hilarious on her struggle to understand her new environment: what was a flannel for? Why did English people wash by sitting in a tub full of stagnant water? Where was the warmth, the human kindness, that she was used to in Iran?
"Yes, it was very traumatic. I reacted by turning away from Iran: all I wanted to do was erase that past. I didn't want to be Kamin Mohammadi, and be brown. I just wanted to be like everyone else.
"We refused to go to Farsi school, or to be friends with other Iranian kids, which in retrospect would have been helpful. But it was a self-protective thing, and it was hard for our parents," Mohammadi pauses, and considers: "But my reclaiming Iran hasn't been easy for them either, because now being involved with Iran means being involved with the Islamic Republic, and they're really not up for that."
As a fellow diaspora Iranian, I understand some of the idiosyncrasies of Iranian family life, the fierce insistence on privacy, and the focus on aberu, or reputation.
"My family have been wonderfully supportive of me as a writer, but the whole aberu thing was an issue," she says. "It wasn't really them, it was me: it runs deeper in me than I realised. Of course, I didn't want to invade the privacy of others. But so often the best stories are invasive.
"I was so scared of showing a draft of the book to my father, and kept putting it off. When I did, he wrote me notes, just factual stuff, this happened then, and so on. The chapters dealing with the revolution were left blank. I said, 'did you fall asleep?', and he said, 'no, you got it right'. And that was it. I thought that very graceful of him. My father is 85 years old now, and an old-fashioned guy, and it must have been very strange to see his life story being told by his daughter. But whatever his private feelings about that, he didn't make them my problem. I thought that was quite beautiful."
It was by examining the relationship between the 1979 revolution and the Mohammadi family that the author came to consider broader questions about the Iranian past and future.
"It strikes me now that I grew up in Iran knowing so little of life outside my own family," she says. "Before writing The Cypress Tree I went back to the history books: I wanted to clarify my thoughts on the history of our country, the character of our people, and the nature of the revolution. I mean, there were members of our extended family who were revolutionaries; they were left wing, they were ideological, they were about freedom and justice. They thought things couldn't get any worse than they were under the shah: how did it all go so wrong?"
The answer, says Mohammadi, lies partly in a lack of social cohesion.
"I've come to the conclusion that we Iranians just don't know one another well enough," she said. "When the revolution started in 1979, it was the first time my family had ever seen those sorts of people, the basijis.
"Today, it's still the same problem. I go back to Tehran and everyone asks: 'Who is voting for Ahmadinejad? Someone must be.' There's such a divide, and I don't think we'll ever make a new society unless we address that."
Despite the repression in the wake of 2009's Green Movement, Mohammadi remains optimistic.
"You know, we are a very old culture. We have assimilated every invader," she says. "Iran won't lose. We - I mean you and I - may never get to live in Tehran, but Iran will be all right in the end. That's part of what writing this book has taught me: to take the long view."
The sentiment conjures up a line from the book, when Kamin's great-grandfather tells her mother: "We Iranians are like the cypress tree. We may bend and bend on the wind but we will never break."