"Ian Rankin was on a train, I was on the platform, so we waved," says Iain Banks, who demonstrates with a surprisingly girlie flutter given the reputations of both men for fictional violence. "And when his carriage pulled away, I flicked the viccies at him."
Banks is chortling behind his whiskers at the memory. There is no rivalry, he insists. But maybe he's relaxed about this because, should there ever be a writerly fight-off, a Celebrity Fifematch, he knows he'll have back-up. Ian Rankin and Iain Banks could, metaphorically, punch to a standstill over creative death. But then the latter would be able to call on a formidable second, Iain M Banks.
Iain Banks writes fiction; Iain M Banks writes science-fiction where the gruesomeness can be even more inventive. No, he doesn't get schizophrenic about which he's supposed to be, or forget halfway through a chapter whether his characters are happily ensconced in Dunfermline (town of his birth) or trapped on the evil planet of Kirkcaldy (a cheap shot at Dunf's neighbour; IMB's writing is more sophisticated than that). In the struggle for supremacy in his study, the score line is 12 books to 11 in IB's favour. But for his new novel Transition the two Bankses have joined forces.
"I just thought it would be interesting," says the author over afternoon tea in Edinburgh's Balmoral Hotel. "I've written a lot of books all told, and I needed the next one to be interesting, never mind anyone else."
In the 1980s, the stark black-and-white dust-jackets of IB's early novels were as emblematic of the decade as Neville Brody's front covers for The Face magazine, and you couldn't travel on a train without tripping over a slouched undergraduate engrossed in The Wasp Factory, Walking On Glass or The Bridge.
But recent IB books haven't thrilled as much. For Banks, they weren't nearly complicated enough. "The process is like building a house," he says. "You need scaffolding for the construction, but you don't want the scaffolding still in place when the job's done." Transition's union of styles, for a 400-page, multiple-narrator yarn, makes for a challenging read.
Don't think Banks at 55 is running out of things to say. Our chat covers a fair range of topics: Barack Obama, Gordon Brown and Abdelbaset Ali Mohmed al-Megrahi, the death of his father, his adulterous past and drugs.
Let's take drugs – marijuana, LSD and cocaine. Banks doesn't, any more. "Do I miss them? Hell, yes. I think virtually everything should be legalised, taxed and made safe, including heroin. Heroin is not that dangerous; it's the impurities which make it so. It is tremendously addictive but respectable studies show tobacco is even more addictive.
"I stopped using drugs recreationally about five, four – maybe three and a bit years ago. My smashing girlfriend is anti them and I just can't be bothered now. I couldn't do cocaine now because, quite apart from the illegality and the health issues, there's the degree of criminality and violence: a lot of people get killed in the supply chain."
Were any of his books written under the influence? "No. Any time I tried it was disastrous. Canal Dreams is the only one I've had difficulty finishing. I was in a flat in Edinburgh which I was keeping way too clean for a heterosexual Scotsman. I was indulging in displacement activity and indulging in whisky. It shows in the text; it's the book I'm the least proud of."
The "smashing girlfriend" is Adele Hartley, a horror filmfest organiser. His divorce from his wife of 25 years has just come through. Other profiles of Banks suggest he's just experienced a midlife crisis, but he says this happened aged 40, when he was with his ex, Annie, but not married to her and he had "two years off for bad behaviour". "I discovered that, bizarrely, the world of publishing is full of smart, young, attractive women. I was selfish, basically." With Hartley he's trying to avoid past mistakes, but adds: "You hope to learn lessons, but often even a writer can't express what they are."
Transition, with its issues of responsibility of power, especially when the moral high ground is adopted, can read like another Banksian swipe at US foreign policy. "Hell, yes," he says, "every possible opportunity, although this time I don't think it was so overt." So what does he make of Obama? "He's not (George] Bush, he's not a moron. In American terms he's of the left and therefore less likely to blow up the world, or small, dusty parts of it." Banks admits he's becoming more grumpy and intolerant "and, I say with pride, more left-wing. At my age you're supposed to go the other way."
Re: Brown, he says Hartley has ordered him to stop saying that the PM lives a "mortar-lob" from him in the 'ferry. "I'm only a little disappointed in him. He's not a war criminal like Tony Blair, he's been unlucky, but he has ballsed up." Banks has never voted New Labour and, after considerable promiscuity with his political affiliations, currently supports the SNP.
"They're doing pretty well, I think, and as regards Megrahi, anyone who followed the trial knows he's as guilty as OJ Simpson was innocent. It was bollocks, the most shameful episode in Scottish jurisprudence in my lifetime, a complete perversion of justice. And for the Americans to say it (the decision to release him] was political – the whole trial was political. The judges delivered what was wanted: by the British and US governments and also by the Libyans, who wanted out from under debilitating sanctions."
Rant over. And interview over too, for Banks must get back to Fife to prepare for the return from hospital of his mother Effie, hurt in a fall. They're both still getting over the death of Banks' father Tom, who died in June aged 91. "I miss him terribly," he says. "I moved them next door to me ten years ago and was round there at 3.30pm every afternoon for tea, except Fridays when Dad and I would break open the whisky.
"He worked for the Admiralty, getting crashed jets out of the water. I maybe toyed with the idea of becoming a navigation officer. Mum would have liked me to have a career in law or medicine, but I always wanted to write, and Dad would say: 'As long as the boy's happy'. I'm an only child, so I was always given all the loot at Christmas and all the love the rest of the year."
Transition is published by Little, Brown (18.99)