I meet MacLeod at EasterCon 2010, Britain's biggest annual convention for science-fiction writers, readers and fans.
With two hours to go before the opening ceremony, the Radisson hotel in Heathrow is packed with oddly dressed people giddy with sugar and anticipation, clutching laptops and novelty stuffed toys and chattering excitedly.
This sense of childish excitement about the future is utterly absent from more bourgeois literary events - you wouldn't find attendees at the Booker prize, for example, dashing through conference rooms and giggling about gay robots while one of the nation's foremost novelists attempts to explain the effect of the evolutionary long-view on socialist thought.
"Science fiction is about prophetic vision - from the most crude and pulpy to the most sophisticated," says MacLeod, who lives in Edinburgh with his wife Carol.
"It's about combining social awareness with elements of scientific truth and speculation."
British writers like MacLeod are universally recognised as working at the cutting edge of science and speculative fiction, a phenomenon MacLeod attributes to the grandfather of British sci-fi - HG Wells.
"The thing about Wells's work that had such an effect on British sci-fi writers is that he was socially conscious," says MacLeod.
"Wells studied biology under Thomas Huxley and assimilated an understanding of human evolution with social speculation, a sense of the transience of human societies within millions and billions of years of deep time."
MacLeod explains that Wells's sense of "deep time" has inspired generations of socially conscious sci-fi writers in Britain, from Arthur C Clarke to Alastair Reynolds, Iain M Banks - and himself.
"If you have a sense of deep time, you can't possibly think the modes of production we have now are necessarily eternal, or even very long-lasting, on a cosmic scale."
It is this aspect of socio-political prophetic vision that places British sci-fi writers at the coalface of literary innovation.
MacLeod's 15 books may feature robots and Glasgow gangsters in space, but they offer prescient and engaging analyses of anarcho-capitalism, libertarianism and contemporary counter-terrorism.
"Science fiction is necessarily political because it depends on what assumptions you have about the nature of society," he says.
"If you believe that all societies are based on natural hierarchy then you will write one kind of story. And if you think that the market is the fundamental principle that societies tend towards, then you will write another.
"Particularly in the 1950s and 1960s, science fiction tended to envision the triumph of the American or Soviet side of the cold war, projected into space, forever. But after the changes of the 1960s, new experiments began to happen in what the future might look like.
"When I started writing my Fall Revolution series, it was against a background of the real fall of the revolution in the late '80s and early '90s.
"I began with a very simple situation - a scientist in the laboratory and a guy with the gun - but I was also thinking about how to create the world they lived in.
"The whole process was informed by the break-up of the Soviet Union and the sense of fragmentation and disintegration.
"Sometime in the backstory of the novels there has been a big swing to the left in the West, which was defeated.
"I no longer define myself as a socialist, but it stuns me that there's a whole generation of growing up - a generation who are younger than my own children - who lack the idea of socialism as an implicit alternative.
"What might a future without any socialism look like? It's not necessarily an attractive prospect."
MacLeod, the son of a Presbytarian minister, was born in Stornoway and worked as a computer programmer before becoming a full-time writer.
As a student at Brunel in the 1970s, he became involved with Trotskyist politics.
"I was a regular reader of the Morning Star back then," admits MacLeod, who fictionalises a future version of this paper in some of his novels.
"For me, in the '80s, the Morning Star was a voice of sanity in a mad world, even if it was sometimes a rather dull voice.
"The second cold war which happened the 1980s was rather frightening and it did look as if the West and the Soviet Union were on a collision course.
"One thing that had a very strong effect on me at the time was the way in which the cold war was actually being fought out in terms of Western-backed counter-revolutions.
"That period hasn't been properly assimilated historically. It was a completely unprecedented, worldwide terrorist campaign by the United States and the United Kingdom against radical regimes."
MacLeod's near-future novels The Execution Channel and The Night Sessions deal directly with what he calls the "blowback" from Western-organised terrorism.
"I've never romanticised terrorism as a strategy, but sometimes it's easy to feel like you have to keep your mouth shut about what you really think - and science fiction can offer a safe space for those discussions," he says.
MacLeod's analysis of far-left movements is far from uncritical. He points out that left-wing movements have been slow to embrace new technologies, in part because the internet "challenges a set of Leninist assumptions that a lot of far-left groups had about how discussions must and should be conducted.
"A lot of the formal rules of the left are still based on 19th-century communications technology - the idea that revolutionary politics are built around a top-level party line set down by a newspaper, which everyone has to agree with. The internet negates that process," he says, adding hastily that "the Star has a head start, in that it allows in voices from outside the party."
MacLeod reserves special disdain for elements of anti-humanist thought in the green movement, which he satirises in several of his novels.
"I think siding with nature against humanity is despicable. The fundamental thing as far as I'm concerned is that you have to judge everything in terms of human interest.
"There is an element in green thinking which rejects this totally and says that the interests of other organisms, and rocks and so forth, need to be taken into account.
"This is not my view at all. I'm quite strongly in favour of humanity developing and improving, and suspicious of the Malthusian logic preached by people like George Monbiot."
So does some green thinking tend towards the fascistic? "It's much worse than that - at least fascism believed in some human beings!"
MacLeod stresses that he does not wish to minimise the seriousness of global warming - merely to critique the anti-human ideology of some green thinkers.
"Global warming is real, it's happening and it's serious, but it's certainly no reason to believe there's more than an outlying possibility of the world coming to an end in this century."
For MacLeod, a central purpose of science fiction is to imagine a future for the human race.
"In science fiction, as in politics, imagining armageddon has the nice effect that you don't have to do anything about it because it's all inevitable and fated anyway.
"We don't know what the future will look like - that's one of the reasons writing science fiction is so rewarding. But there's every reason to believe that human civilisation will continue into deep time."
Printed in Morning Star on 21/10/2010. Ken MacLeod's next book, The Restoration Game, is published by Orbit on 1 July.