Mexican castaway Jose Salvador Alvarenga walks with the help of a Majuro Hospital nurse in Majuro, Marshall Islands. He says he survived 13 months adrift in the Pacific.

Mexican castaway Jose Salvador Alvarenga walks with the help of a Majuro Hospital nurse in Majuro, Marshall Islands. He says he survived 13 months adrift in the Pacific. Photo: AFP

He had the shaggy, unkempt beard, the battered boat and - most importantly of all - an incoherent and fantastical tale of survival.

It is hardly surprising that Jose Salvador Alvarenga, who claims to have spent the past 13 months adrift on the Pacific Ocean, has intrigued so many. He is the archetypal castaway - a figure that has enthralled storytellers and their readers for centuries.

Sian Rees, author of Sweet Water and Bitter: The Ships That Stopped the Slave Trade, who specialises in seafaring history, says: ''The fascination with a real castaway is partly because he is a lone figure. Nobody really knows what has gone on. What did they do to survive? Was there cannibalism involved? Is the story a hoax? It will always be a mystery and you will never truly be able to test their story.''

Mr Alvarenga's story is indeed a mystery. Could the slightly portly chap really have made the 8000 nautical-mile journey from Mexico to the Marshall Islands in the north Pacific, surviving on nothing more than turtle blood, seagull flesh and his own urine? The truth might eventually emerge. Until then, we will continue to pore over every new detail that is published.

And no wonder. An obsession with shipwrecks and castaways is part of the British psyche, etched into our skin like the sea salt that has weathered countless generations of sailors from this island nation.

Shakespeare knew this well enough. He saw shipwrecks and their survivors as the perfect metaphor for reinvention, which is why they crop up so often in his work. As Antonio says in The Tempest: ''We all were sea-swallow'd, though some cast again.''

By the time that Daniel Defoe wrote Robinson Crusoe in 1719, tales of castaways were common fare. Indeed, Crusoe was heavily influenced by the real-life story of Alexander Selkirk, a Scotsman who spent four years on an uninhabited Pacific island after a quarrel with his ship's captain caused him to be abandoned alone while his fellow travellers sailed off. Surviving on seals, goats and island fruit, he almost went mad. He was eventually found by British sailors in 1709 - dressed in animal skins.

Dr Joshua Newton, curator of world and maritime history at London's Royal Museums in Greenwich, says: ''Stories of castaways stretch all the way from Jonah in the Bible to Life of Pi [the Yann Martel novel turned into a Hollywood film]. They are as old as humanity's contact with the sea. However, they exploded in popularity in the 17th and 18th century, when global seafaring took off, especially with the rise of trans-oceanic shipping. For British people, the Pacific was so absolutely vast and fascinating.''

Not all maritime castaway tales were as uplifting as that of Ernest Shackleton and his crew. After his ship, the Endurance, was crushed by Antarctic ice in 1915, Shackleton and four others set off in a lifeboat to find help, leaving the rest of his crew stranded on Elephant Island. Miraculously, everyone survived and Shackleton was declared a hero. Other stories - and this was undoubtedly their appeal - had a darker side.

The most gripping of all is the 1789 mutiny on the Bounty, after which Captain Bligh was cast adrift by mutineers without maps or a compass. Despite dreams of whooping it up in Tahiti, most of the mutineers died either from infection or after being stoned by angry natives.

Of course, part of the mystique of Mr Alvarenga's story is the suspicion that his tale will turn out to be, if not a fairytale, then greatly exaggerated. Only two years ago, a ''wild forest boy'' in Germany, who claimed he had lived like an animal in the woods after his parents had died, turned out to be a hoax. He walked into a police station and declared that he didn't know who he was, thus echoing the long tradition of feral children stories throughout history. It turned out that this modern-day Mowgli was a Dutch 21-year-old called Robin van Heelsum who had got bored with his telecoms job and been living in the woods for a matter of weeks.

Yet we continue to cling to stories of lone survivors for good reason, says Dr Newton. ''We live in a society tremendously dependent on infrastructure, on utility companies to provide us with heat and light, on grocery stores,'' he says. ''The idea of being completely cut off from all this support, being so completely alone, is not only scary but a real fantasy as well. To be beyond the reach of the law, of government, of society - that's what we all sometimes dream of.''

London Daily Telegraph