IAN RANKIN is having a gap year.
"The whole point of having a year off was to gear up for the final two Rebus' novels," he says. "The idea was to think about the series as a whole; what I've not said yet and what I want to say before it ends. It would also have been nice to recharge my batteries."
Rankin made the decision at the age of 25 to set his Inspector Rebus novels in real time. As Rebus inches his way towards his gold watch, it is a decision the author has come to regret. Despite the fact that questions have been raised in Holyrood about scrapping the police retirement age solely to allow Rebus to continue, the next two books will be the last. But, in one sense, Rankin has been gearing himself up for Rebus's final days for nearly two decades.
"It's always in the back of my mind," he says, sipping coffee in the airy sitting room of his home in Merchiston. "What is going to happen in the last book? There has to be some closure on Rebus' relationship with Cafferty, the villain who runs Edinburgh, because they are two sides of the same coin. We could have Rebus and Cafferty locked in mortal combat."
Fans of the series can take comfort from the fact that Rankin is not heartless enough to kill Rebus off. "He's not going to die," he says categorically. "I think he is going to retire to Marbella where he can smoke in the pubs which he won't be able to do in Scotland by the time the final book is published."
There is a good chance, however, that the best-selling fictional detective will go out with a bang, not a whimper. "We could have Rebus and Siobhan, his sidekick, jumping into bed," muses Rankin. "I could never have got them together before because it would have been terrible for their working relationship but then somebody suggested do it on the last page of the last book. It's not a bad idea, actually."
Whatever happens in the final book, Rankin is certain of one thing. "There will be a yawning chasm when I finish. I'm already psyching myself up for it. The final book in the series won't come out to 2007 but I know I will be very upset when I finish it.
"I'm a great believer in the fact that people have only got so many stories in them. I've seen crime writers go on past the point where their character is interesting. They start exaggerating situations because they are bored. Luckily, so far, that situation hasn't arisen but it could happen with the very next book. Having signed a two-book deal, I could sit down and think: 'Christ, there is nothing here'."
It seems remarkable that a writer as prolific and successful as Rankin - his books now sell 500,000 within three months of publication and there have been 20 of them - should retain this sense of insecurity. He really does believe it could all end tomorrow and when that assumption is challenged, he becomes quite agitated. "Every writer should be terrified that the magic is only there for a certain amount of time," he says.
But before he heads into that "yawning chasm", he is busy plotting the penultimate Rebus which will come out next year. This book will be set around the G8 at Gleneagles. "I'm toying with the idea of making Rebus the cop that George Bush cycled into," he says. "I can't find out much about him - everyone is being very hush, hush about it."
Those not familiar with Rankin's oeuvre sometimes wonder about the secret of his success. It undoubtedly lies in the fact that, although a strong character in his own right, Rebus plays a much bigger role. He is a cipher for the nation as a whole and through him Rankin observes the mores of modern Scotland.
"The next book is really going to explore Scotland's place in the world through the metaphor of the G8," says Rankin. "On the one hand we were told that the G8 was a great chance for Scotland to show itself off to the world, on the other hand I think we got badly side-tracked. I don't think Jack McConnell got a very big role to play."
But isn't Rankin's writing another symptom of the Scottish disease - the pick, pick, picking of the scab of identity? Other larger, more confident nations don't seem to feel the need to define themselves by endlessly pulling their constituent parts to bits.
"Maybe," he says. "But I don't think you can change that. You can't change the psyche of the nation. We tend to be quite dark and cynical, partly because we are always being told that we are useless. For a long time we had a chip on our shoulders that we were run by the English and now that we are more than ever not run by the English, we've still got a chip on our shoulder.
"There's always been that pull between the heart and the head. The heart tells you one thing - that you want to be independent - the head tells you not to be so stupid. I hate to go back to this Jekyll and Hyde analogy but there is a tension within us. We look to Ireland and we see the Celtic tiger and how enthusiastic and positive the Irish are about themselves and their country and we think: 'Why can't we be like that?' Well, we're not like that because we're not like that.
"All we can do is point to the more positive aspects of life in Scotland, especially the creative life. Sometimes we don't flag that up enough - the number of composers, musicians, artists, writers, actors we have. But then you look at what the Scottish Executive says about it and it looks very tired and bogged down in bureaucracy. All these badly written reports they bring out about the arts which are full of jargon and dry as dust. It's the antithesis of what they are actually talking about. I'm not saying the arts can cure all the problems of Scotland but we do tend to focus on the negative."
By concentrating on crime in his Rebus novels, Rankin, too, has been accused of negativity. His conscience is as tender as a sunburned neck.
"When you write crime fiction you are, of necessity, always talking about the problems in a society," he says. "In the past I've always maintained that everything I want to say I can say through the medium of the crime novel and that is true thematically. If I want to talk about asylum or race issues, I can do that in the crime novel. But you can't necessarily say how fantastic it is to be in Scotland at this time when everything is moving ahead. That's part of the reason I wrote Rebus's Scotland.
"Scotland is a gorgeous place. This year we went to the Black Isle on holiday. Inverness is a fantastic place to take kids. It's got everything. And you think: 'Maybe I could use that in a book'. But Rebus wouldn't go dolphin watching in the Moray Firth. All he would do is say: 'Inverness is grubby and the pubs are bad'."
It sounds like he is falling out of love with his creation. "No," he says. "But my mindset now is that the series is winding down. I always knew that this was a series with in-built decrepitude. Hopefully, once it ends I'll have other things to say.
"The thing that keeps most people writing is that they still have not written the perfect book. Is there such a thing as the great Scottish novel? Probably not and if there was it would have to be a series like Anthony Powell's Dance To The Music Of Time because you could never say everything there is to say about Scotland in one book.
"Lanark comes pretty close but Lanark is a very Glasgow novel. Writing the great Scottish novel is not something you can plan to do. If you do it at all, you do it by accident."
Great Scottish novel or not, Rankin's place in the literary canon is secure. His work is studied in numerous universities. Earlier this year a first edition of the first Rebus book, Knots and Crosses sold at auction for 300. "It was really weird," he says. "There they were bidding for Oliver Cromwell's signature and the next lot up was Ian Rankin books."
It cannot be long before somebody attempts to write his biography. He winces at the thought.
"I'm not very interested in examining the inside of my own head, I'm much more interested in examining the inside of Rebus's head." There is, however, a small goldmine awaiting anyone bold enough to take on the task. Rankin's obsessive nature means that he kept a daily diary for 20 years.
"I've still got them," he says. "It's all rubbish - right up until the age of 30 it's rubbish. I've got to put instructions in my will for them to be burnt. All these mentions of Top of The Pops."
Why did he keep them, then? "Because somebody gave me one and I felt I had to fill it. It was a page a day every day for 20 years. If I was running short, I'd fill in my top five albums, fill it in any way I could. I'm a creature of habit. I go to the Oxford Bar or Bennett's Bar. I'll go to the caf every day to read the paper, do the crossword and drink a couple of cups of coffee and that is when I am happiest, on my own. I think all writers are. We're not gregarious."
There is much more to Rankin than that. The perennial outsider - "I live in Edinburgh but I don't feel part of it. At best I feel part of part of it" - he has given Scots a rare, dispassionate insight into their nature. Long after John Rebus has solved his last case, the conundrum that is Ian Rankin will continue to fascinate.