Alexander McCall Smith: The No1 novelist's guide to Edinburgh

Pinning down Alexander McCall Smith is no easy feat. To give us an idea of what we're up against, his publicist offers a glimpse of the writer's diary when I first call to arrange this interview: "Dublin Friday, London Sunday, events there all day and night until Tuesday; then it's the Essex book festival. Returns to Edinburgh on Wednesday – appointments all day and an event that night. Thursday is World Book Day and he is in the Scottish Borders.

At the weekend it's Dubai for the literary festival, and then Hong Kong." So – sorry! – no can do. For weeks it goes on like this. Then, just at the point where disappointment turns to rage and I'm beginning to imagine pinning down the 61-year-old author of the The No. 1 Ladies' Detective Agency more literally, in a headlock (in the unlikely event that our paths should ever cross), a deal is finally brokered. There will be coffee at his Edinburgh home, followed by a guided tour of the New Town – where his latest 44 Scotland Street story is set – on what turns out to be a spectacularly rain-sodden Tuesday morning in June.

When we do finally meet, any previous desire to inflict bodily damage on my host, the revered professor of medical law and expert in bio-ethics turned best-selling novelist, soon dissipates. For one, he is rather tall, which would give unfair physical advantage. Plus, he is wearing a suit – linen, pinstripe, and made-to-measure by Mr Chen, "a jolly good tailor" in Hong Kong – and no one wants to see a grown man tussle in a suit. Then there's the matter of those "feather-light" ostrich-skin Belgian shoes (he has a lizard-skin pair too), with their compressed horse-hair soles, which would no doubt make for a nimble opponent.

In any case, on close inspection, the Zimbabwean-born novelist isn't a hittable man. Not only is he terribly jolly – in spite of the difficult circumstances, which will soon become apparent – but he reveals a tendency to mock Belgium at regular intervals, which at the risk of sounding racist, is mildly endearing. "You don't associate Belgians with footwear, you think they only make chocolates and regulations," he remarks at one point in a refined Scots lilt, having removed his left shoe and thrust it in my hand for closer inspection. "And yet here they are, allegedly making these! Remarkable."

The McCall Smiths reside in a large Victorian villa standing back from the road on a quiet, tree-lined street in the Merchiston area of the city. Merchiston is home to a number of high-profile literary figures, and McCall Smith can claim to know the best of them. JK Rowling has a house here, and one of McCall Smith's closest neighbours is the crime writer Ian Rankin, who strides past me up the hill as I arrive. "On his way to Starbucks," says McCall Smith. "We often meet there for morning coffee."

Today, however, Sandy, as he likes to be called, is making his own coffee, retrieving skimmed milk from a huge pillar-box-red fridge, which he heats on the Aga in the kitchen – "the only modern room of the house". It looks out on to a large garden through wall-to-wall glass sliding doors. McCall Smith and his wife, Elizabeth, a recently retired GP, have lived in this house for 26 years, "or a quarter of a century past, if we are to take the long view". In this time they have gone to great efforts to return it to its former Victorian glory.

The rooms, of which there are quite a few, are incredibly spacious, with restored traditional features: beautiful carved-wood borders and cornices line the upstairs hallway. Across the house, almost every wall and surface is covered in pictures and curiosities picked up on travels to far-flung lands, with a fair few copies of the homeowner's work among them. Next door to the writer's study, there's a room dedicated to foreign versions of his books, which he leafs through excitedly, translating their titles from Swedish, Estonian, Thai; a stack of The No. 1 Ladies' Detective Agency audiotapes stands neatly displayed in front of a marble fireplace in the drawing room.

Back in the kitchen, having pointed out Ian Rankin's garden fence, which can be clearly seen from here, McCall Smith tells me that the house was previously owned by a famous manufacturer of fireplace surrounds, Thomas Bogey. The light from the window illuminates a silver nest of hair as he talks. "And until the 1950s, this had been a home for fallen women – in the days when we still had fallen women!" Chuckle, chuckle, chuckle.

By the time I arrived at 9am, Alexander McCall Smith had already been up for four hours, having worked until midnight the previous evening. "I have odd hours," he shrugs. "Sometimes I wake up at 3.30am to work through correspondence." This morning he's also written 1,500 words towards one of several novels he currently has on the go, and is ready to talk to me about his latest 44 Scotland Street story, The Importance of Being Seven, which will be published next month.

44 Scotland Street first started life as a weekly serial in The Scotsman, and is now in its sixth novel. After a two-year gap, The Importance of Being Seven continues the tales of characters such as Cyril, the gold-toothed canine with a taste for beer, and young Tofu, whose father writes highly influential books on such subjects as the energy field of nuts, their lives intertwining on the streets of Edinburgh's prosperous New Town. In chapters with simple, reassuring titles such as "A Timetable of Happiness" and "A Very Considerate Husband", their daily affairs are peppered with gentle moral musings – for instance, who, in a situation where two people approach a door at the same time, should be allowed to walk through first? The answer, we're informed, relies on "a system based on common courtesy and consideration, mixed with a measure of sheer practicality. In general, women should be invited to precede men, not because this is any way endorses chivalric notions that many may now find awkward or even condescending, but because it provides a totally arbitrary rule that at least minimises the chances of congestion". There are, too, frequent references to some of the writer's cultural heroes, including WH Auden and the Scottish painter Sir Henry Raeburn.

There is no high drama on Scotland Street – unless you count Antonia McDonald being struck by Stendhal syndrome on a trip to Florence; no tragedy; no unhappy endings. It is all, in theory, nauseatingly nice. And yet it is that all-prevailing pleasantness, the unfaltering optimism and the gentle pace of life that holds the key to McCall Smith's success. It is his ability to transport readers to a simpler world which has, as my taxi driver would have it, made the man "a fook load a money".

In the past 10 years or so, McCall Smith has become – in his own words – "one of the biggest literary enterprises in the world"; his is now a brand involving 50 publishers across the globe. His books – which are translated into 46 languages, with particularly high readerships in Sweden, Singapore and the United States – have sold more than 40,000,000 copies to date. Maintaining this position involves a mind-boggling schedule of literary events, dinners, talks, signings and social events both here and abroad, while responding to a constant barrage of readers' letters. And all that alongside the small matter of churning out an average of four to five books a year.

In order to keep tabs on where he's supposed to be from one minute to the next, the father-of-two has an agent in London, another in New York, and employs two personal assistants, one of whom keeps an office in his house. She manages his diary completely, printing out a daily programme for her employer. It all sounds terribly grand – if not exhausting – and yet, it was not so long ago that this former academic was leading a rather different life.

Before becoming a bestselling novelist, McCall Smith spent much of his career as a legal academic and professor of medical law, "with a personal chair at the University of Edinburgh". He latterly stood on various committees, including the Unesco international bio-ethics commission and the human ethics commission in the UK, where he was vice-chairman under the revered Helena Kennedy QC. All the while he'd been writing in his spare time: short stories, children's books and radio plays, and had in fact already written more than 30 books by the time the The No. 1 Ladies' Detective Agency was published in 1998.

But it wasn't until his tale of "traditionally built" Mma Ramotswe, who wiles away the days philosophising and quietly righting wrongs on the streets of Botswana, was released (at first only in a very small edition) that the world took any notice. The book subsequently became an international bestseller, spawning many sequels (there have been 10 to date, plus Mma Ramotswe's Cookbook) and was adapted for the screen by the late Anthony Minghella. Since then, there have been times, the writer admits, when he has had to stop and pinch himself: "Though I have stopped pinching myself now."

Born in 1948 in the British colony of Southern Rhodesia (now Zimbabwe), McCall Smith went to a Catholic boys' school, "although we weren't Catholic", which, he says, was "OK in parts". He moved to Britain at the age of 19 to study. His father, a Scottish public prosecutor and his mother, who spent a long time working on a novel which she never finished, returned to the UK in the 1970s. His mother died shortly after that, while his father lived to the ripe age of 86, marrying Doreen Salmon, the daughter of JA Hunter, "the great hunter in East Africa", at the age of 69.

It was after his first secondment to the University of Botswana to help set up a law faculty, that McCall Smith married Elizabeth, in 1981. They'd been introduced while studying at the University of Edinburgh, and re-met later down the line. Today, they have two grown-up daughters. Just a few days before this interview took place, Elizabeth was told she has bowel cancer and was taken for treatment. Due to an early intervention, the prognosis is good. McCall Smith refused to cancel our interview, despite having to pull out of several literary events, and is in remarkably positive spirits.

Elizabeth stopped work as a GP last year, her husband explains, once we're settled in the drawing room, sipping coffee from cups and saucers and watching the street below through wide bay windows: "Our life is so sort of hectic now, with me having to travel so much, it was really beginning to be rather difficult." So far this year, the pair have travelled a "pretty standard" amount: January, the Jaipur literary festival, then Australia for a "shortish" tour. From there, Singapore, Dubai, for the Emirates literary festival, and on to Hong Kong. There would have been an American tour somewhere in between, but for the Icelandic volcanic-ash debacle.

Later this year it's Canada, then Sweden, and finally, the States for a tour which will mean a different city (and therefore a flight and a different hotel) every day for as long as it lasts. "That's my life," he concludes with a shrug. "It sounds very exotic but really it gets very, very demanding." Does he ever yearn for a quieter existence? His face grows momentarily pensive. "There are times when you think: 'Heavens, what am I doing this for?'"

None the less, McCall Smith is "a man of great ambition", and his demeanour perks up no end as we move seamlessly on to a subject close to his heart: pigs. "Who can't like pigs? They're wonderful creatures! I've always liked pigs." So much so that, on top of everything else, he's recently set up a company to breed British saddlebacks: "Though I won't be actually looking after the animals on a daily basis." He's also a big fan of tea: "I'm very interested in tea. I wouldn't mind being involved in some aspect of the tea industry." And, of course, shoes: "I am a big fan of shoes," he says, though disappointingly, he has no immediate plans to launch his own range.

In his "downtime", he and Elizabeth like to play bridge with friends: "I like to do the same things, to see the same people," he says. "The local community is very important in one's life; the feelings of identification with a place and people." He can't imagine living anywhere other than Edinburgh. "Such a civic society," he says, suits him well. Every year in June and July – two months kept relatively free from work – the couple spend time at the house they own on a sea loch in Argyll on the west coast of Scotland. "At high tide the water is just 30 feet from the front door. We have a mooring out on the loch, so we use a small boat to go out to a slightly bigger boat, and pop over to Mull and Tobermory to do our shopping."

He also likes to spend time with his children, both of whom are at the house today. Lucy, who is 25, has made the journey to visit her mother from London, where she's studying medicine at King's College. She's recently bought a place with her boyfriend in Brixton. "The estate agent referred to it as the Clapham Borders," says McCall Smith. "The Clapham Borders! Would you believe it?" Ha, ha, ha. Emily is 23 and a medical student in Edinburgh; she is busy studying for her finals, and as we prepare to head out into town, we find her huddled over her notes on the kitchen table, nursing a can of Diet Coke.

"We're both rather taken with this stuff, aren't we Emily," her father says, pulling another two cans from the fridge, for the journey. Looking even more dapper now, having accessorised his outfit with a brown felt hat from Ecuador and a long dark green trench coat in preparation for the relentless rain, McCall Smith leads us out to where our carriage – the writer's chauffer-driven Jaguar – awaits.

The first and only time I have been to Edinburgh before now was long ago on a school trip, aged 13. Choice memories include knocking over a display pyramid of Wonderbras in Jenners department store, smoking cigarettes in a graveyard, and seeing my classmate punched in the face by a stranger in broad daylight. None of this, however, would ever have happened in Alexander McCall Smith's Edinburgh. His is a gloriously anachronistic, genteel landscape, as demonstrated in 44 Scotland Street where characters called Angus Lordie and Domenica MacDonald share mildly disapproving conversations over tea supped from blue Spode cups. As our car heads through Morningside towards the New Town, my companion observes: "I was walking behind a couple of Morningside ladies recently. One turned to the other and said: 'Will you just look at the state of the pavement?' The other nodded: 'Just like the rest of the world.' "

The idea for the book first arose, McCall Smith explains, in San Francisco, at a party held in his honour by the Chinese-American writer Amy Tan. "I was talking to Armistead [Maupin, author of the Tales of the City series] at the time." Soon after, six-year-old Bertie Pollock – the story's accidental hero – was born. Today, we drive past the spot where the long-suffering brother of baby Ulysses and the son of Irene, who insists her "preternaturally gifted" boy lives in a pink room ("it's society that tells you pink is for girls, Bertie") stares longingly out at the treetops from the waiting room in his psychologist's office. Irene insists on regular appointments for her son, to monitor any latent Oedipal urges, which he attends – along with his weekly Italian and yoga classes – with a growing sense of doom.

Today, an official map, "In the Footsteps of... 44 Scotland Street", guides fans through relevant points of interest, such as Drummond Street Gardens, where Cyril the dog had his brief love affair which spawned six puppies – an "event" which triggered "terrific response" from readers all over the world. Then there's the spot nearby where Scotland's First Minister Jack O'Connell saved Bertie from being run over. A number of real-life characters make appearances in the books, but only once the writer has obtained consent. He'd sent the proposed passage to O'Connell's publicity team, just after the politician had suffered a bout of bad press. "Most satisfactory," read the response. An appearance in 44 Scotland Street, after all, is a bit like being touched by the hand of God. The owner of the Cumberland Bar, which features in the books, ran up to McCall Smith in Waitrose recently and thanked him profusely for the inclusion, which has boosted business no end.

Today, a day so bleak that no one in their right mind would choose to leave the house, we encounter several couples following the Scotland Street trail. Each approaches their favourite author as if he were an apparition: "I just can't believe it's you," one woman gasps, seemingly close to tears. He takes it all in his stride, posing for pictures and chatting away as if to old friends. Does this happen a lot? It certainly does.

After a quick call-in on Iain McIntosh, the artist who illustrates the 44 Scotland Street stories, at his New Town studio (the lion's head knocker on his door inspired the book's cover), it's off for another hit of caffeine, this time at Glass & Thompson, the café immortalised in another of his books, before our last stop, a photocall on Heriot Row: "One of the finest streets in town," my guide announces as he assumes his pose. At that moment, a woman walks past with her dog, nodding politely to McCall Smith as she passes. "It would be nice to have the dog in the picture," he calls after her with a grin. She turns, and in a knowing voice, replies: "My dear, this is Edinburgh. He is a lurcher. I'm afraid it simply wouldn't do".

'The Importance of Being Seven' by Alexander McCall Smith is published by Polygon on 1 July