Adventurers cut quite a dash in our imaginations. Stereotypically, they are Hagrid-sized figures who are never happier than when braving the elements, growing beards, communing with nature and wearing baggy trousers with a thousand and one pockets to store useful bits of kit. Transport them to an urban setting and they look as out of place as a huskie in a poodle parlour. Tim Severin has been hailed as the "greatest living explorer" by his many fans, the heir to the celebrated Thor Heyerdahl of Kon-Tiki raft fame, and the veteran of a dozen or so intrepid journeys around the globe. He has recorded them in prize-winning films and books like The Brendan Voyage, his much-reprinted 1978 account of sailing the North Atlantic in a tiny leather boat in the footsteps of the sixth-century Irish saint reputed to have discovered North America.
So I have a fairly clear image in my mind of the 64-year-old man who will be waiting for me at his publishers' London office. Instead it opens to reveal a dapper, upper middle-class Englishman, immaculately groomed, in a well-fitting tweed jacket and wearing a cravat. At first glance, he is more captain of the golf club than Sir Ranulph Fiennes.
My surprise must have shown on my face. "The best article ever written about me," he confides, "is from an American magazine called Outdoor. It labelled me 'Captain Retro'". He pauses for a warm, putting-you-at-your-ease laugh. "And it's true. I don't fit in with this age of celebrity travellers. I once did a book tour accompanied by a publicist with a beard and everywhere we went people would walk up to him and say, 'Hello, Mr Severin.'"
His refusal to play up to expectations has stopped Tim Severin achieving quite the instant recognition of some more obviously rugged colleagues. Plus his natural reticence: in his dozen or so written accounts of his replica journeys, he sticks to his theme and never indulges in Ellen MacArthur-like monologues mapping his emotional mood-swings. To do so, you sense, would be for Severin to distract from his seriousness of purpose. And in the films that he has made of his journeys, he stays resolutely behind the camera, observing not blocking the view. "I've always been accused by my editors of never putting enough of myself into my books," he says with no hint that he plans to reform his ways in his voice.
Such an emotionally continent approach may have cost him profile, but it has a flip side - a devoted fan-base of similarly serious-minded folk. Severin has won so many awards that he professes - genuinely, I think - to have forgotten which book each one honours. And then there are the degrees and medals for geographical and maritime societies.
Now, however, this intensely private and unrepentantly old-fashioned writer is about to expose himself as never before with the publication of his first novel, Viking: Odinn's Child (Macmillan, £12.99). He is, in his own words, "spinning the mirror". He has spent his adult life taking historical legends and showing in detail how they might be fact. Sinbad the Sailor, Jason and the Argonauts, Robinson Crusoe, and Ulysses have all been given the Severin treatment. He is now doing the opposite. In the novel, the first of a series of three to be published this year, he charts the early years of Thorgils Leifsson, born in 999, grandson of Erik the Red. The Viking empire, reaching out to North America, is coming under the spell of the "White Christ", or Christianity. Thorgils, as he travels between Greenland, Iceland and Ireland, fights to preserve the old ways and deities. Gifted with second sight, he is pagan mystic and warrior.
"I did feel a little bit queasy at first at the prospect of publishing a novel," Severin admits. "My readers have grown to expect me to be matter-of-fact, but in fiction you must write about people and emotions. That is new to me and a little unsettling when you are used to keeping such emotions out of the narrative".
So why has Severin taken on a challenge that seems to go against both his personal predilections and his public pigeonhole? Commercial reasons may have played a part. Historical fiction is very fashionable indeed. His publishers, Macmillan, have been doing a roaring trade with writers like Valerio Massimo Manfredi and Max Gallo, who have rekindled with novels about Alexander the Great and Napoleon a market that had all but become extinct since the heyday of writers like Mary Renault in the 1960s.
The Manfredi trilogy was published over a single year and clocked up sales of 200,000. Severin's publishers have high hopes that the Viking troika, marketed in the same way, will match this achievement. The author himself gently scotches any notion that he is chasing readers in a cynical fashion. Odinn's Child, he says, has been in his desk drawer for almost 20 years. "Between expeditions," he recalls, "I'd pull it out and add a few chapters and then go off and chase Moby Dick or whatever. Then I'd come back. There would be a hiatus, and I'd do a bit more on it. And then, after the Robinson Crusoe project, I came back and thought: 'Do I really want to climb the mast of a small boat in a howling gale again?'... So I tried to think of something else to do and pulled the manuscript out again, thought this isn't bad, and it went from there."
The Viking theme has been a long-term obsession but it never sat easily with the more conventional Severin approach. "Again and again, over the past goodness knows how many years, people have said to me: 'Why don't you do a Viking voyage, build a Viking ship, sail to Greenland?' But others have been doing that since 1890, some of them extremely well, and I couldn't see the point in copying them. Yet when I looked at the fiction that has been published, based on the Viking sagas, I found that no one had done anything decent for about 50 years." There was more to this change of direction, though, than the creep of the years and the search for that elusive something new.
Severin believes that we are fast approaching overload in terms of public interest in adventurers. So has his wanderlust deserted him for ever? The man he describes as his guru - the Norwegian pioneer of voyages to investigate legend, Thor Heyerdahl - was, after all, active and curious into his nineties. "I wrote a foreword recently to a new edition of Kon Tiki," says Severin, "and I reread the book after a 30-year gap and was surprised quite how good I still found it." If pressed, he doesn't rule out another journey. And he's in good shape, so there's no health reason for him to hang up his waterproofs. Indeed, there have been brief moments when the travel bug returned during his research for Odinn's Child.
Needless to say he took this aspect of historical fiction very seriously indeed. "At the mouth of a fjord on the north coast of Iceland, there is an island which is just like an iceberg. It's the location of a major episode in one of the main Norse sagas. I wanted to go there so as to make it a location in the book. Three or four Icelanders said they'd come with me because they'd always wanted to go but it was so difficult to get to. We went out in a boat and climbed a rickety old ladder pinned to these sheer cliffs. When we were finally standing up on the top with these fabulous view, one of them started to recite in Icelandic the verse from the saga about the island. It was quite something."
Severin's fiction may not have a direct link with a single journey, but it does also inevitably draw a good deal on his experiences. So when he writes about Thorgils 's travels across the North Atlantic in his Viking boat, Severin is basing his account on his own trip from Ireland to Newfoundland in a leather curragh for The Brendan Voyage. He has a huge reservoir of material waiting to be turned into fiction. Or possibly an autobiography? "No, no". He's laughing but emphatic. "I think one remains private".
Although a late convert, he seems at present to relish novel-writing. "I did worry at first that what I was doing was lightweight by comparison with what had gone before. As writing progressed though I got much more comfortable with it as I realised just how much fact I could get into the text. I always felt on my journeys that they were only worth doing if one had a chance of improving knowledge. Now I can see the same applies to these novels." Viking may be aimed squarely at a popular market but, in his novels as in his travels, Tim Severin remains on a very Reithian mission to educate.
Biography: Tim Severin
Tim Severin was born in India in 1940 and read geography at Oxford. His first book, Tracking Marco Polo (1964), was an account of the trip he took as a student from Venice to China on a motorbike. He has subsequently crossed the steppes of Mongolia on horseback (In Search of Genghis Khan, 1991), the Pacific on a bamboo raft (The China Journey, 1994), and the Mediterranean in a recreated Bronze Age galley (The Jason Voyage, 1984). He lives in Cork, Ireland, and writes regularly in National Geographic. He has won the Book of the Sea Award, the Thomas Cook Travel Book Award and the gold medal of the Royal Geographical Society. His first novel, Viking: Odinn's Child, part one of a trilogy, is published today by Macmillan.