Bob Bob Ricard, Kazuo Ishiguro’s favourite London restaurant, on the corner of Beak Street, Soho, has upholstered booths that make it look like a luxurious railway train – the Orient Express, perhaps. We settle in at 1.30pm for what will turn out to be a long journey, with a conversation sprawling, various and with multiple destinations. Ishiguro sits opposite in his habitual uniform of black jacket and shirt. His hands are expressive and he steers the conversation with such freedom that questions seem cumbersome interventions. He has claimed he is not a novelist reliant on observation (his Booker-winning novel The Remains of the Day and 2005 sci-fi hit Never Let Me Go share a “tweaked” reality). Yet he is all attention – a good watcher and listener.

Before we get on to his seventh novel, The Buried Giant, “Ish”, as he tends to be called, wants me to admire the plug socket next to him. With a child’s delight, he reports that this restaurant once him served afternoon tea and plugged in a toaster at his table. Even better, I suggest, is the bell at my elbow instructing, as if anticipating an emergency: “Press for champagne”.

I confess to Ishiguro straightaway that I approached his new novel nervously. I have a blind spot about Arthurian legend and thought I might need rescuing from a novel that involves dragon-slaying and a latter-day Gawain. But I was relieved to find the book has what all his best writing possesses: an understated, enigmatic narrative, filled with melancholy truths. And Gawain, with his ancient armour and faithful horse, has a sympathetic affinity with Stephens the butler in The Remains of the Day. “There is a real dignity and a romanticism about both of them. They are pathetic and sad because they are out of time,” he says.

The Ice Hotel by Stacey Kent, lyrics by Kazuo Ishiguro

Above all, The Buried Giant is a journey of a book and makes me wonder what Ishiguro sees as the most significant trip of his own life. I expect him to describe his departure, aged five, from postwar Nagasaki, leaving his grandparents and coming to Guildford, Surrey. But he chooses his gap year hitchhiking around America. And he makes travel sound like novel-writing – only it was his own character he was working on: “At that age, you keep pretending to strangers you are somebody else, it is a crash course in reinvention. Nobody knows you, so you are an introverted, sensitive person one day and a noisy, boozy, gonzo character the next.”

On the subject of reinvention, it becomes clear that, although he grew up speaking Japanese, he feels British, “not just because I have a British passport but because I know the different layers of southern England”. When he first came to the country, he was in the local choir. England has changed since those days. He hates the “clone-town” phenomenon that has overtaken places that once seemed individual. And he feels northern England has been betrayed, that mining and manufacturing communities were “sold a dream of the future in the 80s yet little has been done to regenerate them or replace their industries”. He goes on unexpectedly to say: “I love living in London, but if I had to write a ‘London novel’, I’d portray the capital as a vampire sucking the blood out of the rest of the country. I’m amazed people in Britain accept so quietly this lack of regional balance.” Ishiguro also has great feeling for Scotland, partly because of his Scottish wife, Lorna MacDougall (with whom he has a 22-year-old daughter).

His parents never returned to Japan. His father was an oceanographer, working for the British government. It is only now, aged 60, that Ishiguro can see a resemblance: “Physically, we are very different. But now, I recognise certain things I must have got from him. He had this ability to get on with his own work. Neither of us needed someone to come along and commission us – and we built up a resistance to doing stuff apart from what we really wanted to do.”

His father was the inventor of a “massive” machine that measured tides: “When my father retired, it ended up in my parents’ garage. It was really heavy and looked like the inside of a Tardis. My father died in 2007 – my mother is alive and well but has been worried about what on earth to do with this huge thing. The fantastic news is that, last summer, the Science Museum decided it was of historic interest. My mother was so relieved somebody was going to take it away.”

In his youth, Ishiguro styled himself as a singer-songwriter, although his paid job, in his early 20s, was working with the homeless in London. In 1980, when he went to the University of East Anglia to study creative writing, he realised he couldn’t hope to excel as a songwriter and a novelist. “I used to see myself as some sort of musician type but there came a point when I thought: actually, this isn’t me at all. I’m much less glamorous. I’m one of these people with corduroy jackets with elbow patches. It was a real comedown.”

He starts to enthuse about the jazz singer Stacey Kent and her jazz saxophonist husband, Jim Tomlinson. Kent and Ishiguro met after he picked her singing Gershwin when he appeared on Desert Island Discs. She asked him to contribute some lyrics to what became 2007’s Grammy-nominated album Breakfast on the Morning Tram. The tram was borrowed from the end of Ishiguro’s fourth novel The Unconsoled and he explains the reference: “You have been up all night – heartbroken – but, in the early hours of dawn, you get on this tram and it is full of these commuters who are terribly cheerful and comfort you, and there is a buffet at the end of the tram and it has everything you want – fantastic coffee – and everyone chats to you and you stuff yourself with croissants.”

Waiter Oh, Waiter. Lyrics by Kazuo Ishiguro

Ishiguro goes on: “One of the key things I learnt writing lyrics – and this had an enormous influence on my fiction – was that with an intimate, confiding, first-person song, the meaning must not be self-sufficient on the page. It has to be oblique, sometimes you have to read between the lines.” He likes to “audition” characters as first-person narrators – ever since he made a small boy narrator of his second novel, An Artist of the Floating World, and later had to “sack” him. Ichiro was the grandson of the protagonist and An Artist was “my first in-depth first person narrative, following labyrinthine meanderings inside the main character’s head… Ichiro as a narrator would have meant observing this inner struggle from the outside – and probably with a dose of irony, given the boy’s age.”

After our robust fish pie and lemon sole goujons, we have both ordered blameless sorbets. And with the change of course, the conversation shifts again. The Remains of the Day and Never Let Me Go were both made into films and he mentions that producer Scott Rudin has rights to The Buried Giant. He’s intrigued by the differences between literary and film PR.

“In cinema, there is this idea that the work has to be created in a completely harmonious environment – any slight disagreement they think terrible publicity. Whereas for a novel, you want to hear: ‘I had to abandon the book, was tearing my hair out, thought I’d give up writing altogether, became a drug addict and then produced this torment…’” He laughs. “It is the complete opposite in film.” And he starts to explain how “the best media trainers in Hollywood, Twentieth Century Fox” got to work on the cast of Never Let Me Go. He was impressed.

About this, we disagree. I protest about blandness, he makes the case for actors fearful they will never work again if they fail to say what is expected. I complain about what I call “professional enthusiasm” and he seems to take the point. But by now, it is four o’clock and we are still talking. It is time to call it a lunch. It is only when I get home that I listen to the comic song Ishiguro claims to have enjoyed writing most Waiter, Oh Waiter, from Stacey Kent’s most recent album Changing Lights. It is set in a restaurant:

“Waiter, Waiter, Waiter, Oh Waiter / Please come to my rescue / I cannot understand a word that is written on this menu / Not that I’m unaccustomed to this kind of smart cuisine / But what you have handed me is in a language I have never seen…

And the way my companion here keeps gazing over at me / Makes me feel like I’m drifting further and further out to sea…”

Chez Bob Bob Ricard, it seems we got off lightly.

Kazuo Ishiguro ate: Siberian pelmeni, fish pie and spring greens. Kate Kellaway ate: cheese soufflé, lemon sole goujons and spring greens. Both had trio sorbet for pudding; Bob Bob Ricard , 1 Upper James Street, London W1F 9DF, tel 020 3145 1000.

The Buried Giant is published by Faber, £20. Click here to order a copy from Guardian Bookshop for £16

