Rotted shark, breast of puffin, sheep's head, ram's testicles, skyr (a cultured milk preparation served as dessert), blood pudding ... Iceland's traditional foods are not for those of a sensitive disposition or delicate stomach. Which might explain why, though you can go to a restaurant in London and order food from just about anywhere else in the world, if you want to eat Icelandic, you really do have to go to Iceland.
And despite the climate (averaging 10C in summer, -0.5C in winter; in other words, even more miserable than Britain) and the prices (£6 for a pint of beer, anyone?), going to Iceland is exactly what thousands of young Brits are doing every weekend. On Fridays they catch a flight from Stansted (it is surprisingly cheap, at £118 with British Airways' budget airline, Go) and head three hours north to a land of lava fields and glaciers, to spend the weekend lazing in geothermally heated pools and exceedingly laid-back nightclubs. But what do they find to eat when they get there?
Putrefied shark sounds like the sort of thing you'd only swallow for a bet - and that's even before you learn that freshly caught Greenland shark is poisonous because of its cyanic acid content. But some centuries ago, Icelanders discovered that if they buried the carcass and left it to ferment for a few months it didn't actually kill people when they ate it, hence the now pungent national delicacy. As an island - and a northerly one at that - Iceland has had most of its cuisine dictated by the edibility of the wildlife and the need to preserve it. So fish comes sun-dried (eaten as a snack, or before a meal, torn apart and softened with a little butter); meat is saved every which way it can be; and every part of a beast (and I mean every part) that may plausibly be transformed into some nutritious meal has found its way into the recipe books.
Iceland's favourite son, Magnus Magnusson, tells me with relish that whenever he goes home he returns with suitcases heavy with food. "People laugh at these things, but I love it all," he says. "Especially sheep's head, although I'm afraid that's considered rather infra dig these days. Icelanders are like, 'Oh yeah, sheep's head, we're past that - we don't eat it any more.' But I adore it - the meat around the jaw is marvellous."
Being in Iceland feels like being on the very cap of the world. The clouds are so low that the gap between sky and earth seems impossibly slender. Even in early September the sea air is harsh and unforgiving. The low-slung houses, all painted red, blue, white and green, seem hastily erected from planks of wood and corrugated iron. The capital, Reykjavik, is so tiny (its population is just 110,000) that virtually wherever you are you can peer down some street to the grey waters of the harbour where the fishing vessels are lined up in front of the fuel tanks.
Around the edges of the sea, volcanic cones arch angrily upwards, as if no other land had any business being there. And in front of the cathedral - a huge concrete arrow that looks like something from Star Wars - stands a statue of a proud, armour-clad Norseman: Leifur Eiriksson, an 11th-century navigator and son of Eric the Red, who discovered the coast of America before Christopher Columbus.
Against this atavistic backdrop, sheep's head and sharkmeat don't seem so out of place. They are still eaten, and celebrated each February at Thorrablot, the festival of the month of sour things, when Icelanders traditionally feast on preserved foods. Yet like the rest of us, Iceland has succumbed, in part at least, to what has become the bindweed of the kitchen - Italian fast food. This foreign invasion (and yes, there is also a McDonald's in Reykjavik) may be keeping the tourists happy, but this is evidently of great concern to some of the natives. "Before the recent onslaught of nouvelle cuisine, pizza and pasta," froths one recipe book I found, "Icelanders ate wholesome meals majoring in fish and lamb."
Some restaurants have tried to compromise by taking the modern European style of cooking and substituting a few local ingredients. This week I dined out on smoked breast of puffin (apparently once a vital part of Icelanders' diets, now considered rather a delicacy) with deep-fried carrots and carpaccio of dolphin with a marinated tomato salad. The puffin meat was very dark - the colour of dried blood - and exceptionally tender, though so thoroughly smoked I could discern no other flavour. The dolphin was also deep-coloured, and tasted a little like very thinly sliced raw beef.
There were chewy bits (muscle, presumably) that my teeth couldn't bite through; the rest was tender. The waiter explained that dolphins tend to be tough and must usually be "boiled and boiled and boiled" to render them edible. I could not quite believe that I was eating real dolphin (there is a creature called a dolphin fish, but it swims in tropical or semi-tropical waters). Later I was told that it had indeed been "real": Icelanders eat the very small dolphins - hrefnakjot - that get caught in fishing nets, "but perhaps you shouldn't write about that in a British paper. It will not be very popular."
Still, there was no sign on any menu of the famous rotted shark. The twin receptionists at my hotel launched into a rhapsodic double act when I mentioned it. "We have it at home all the time," they said, smiling. Rotted shark, they continued, is said to be good for the stomach, is usually eaten before a meal to help counteract the effects of the great quantities of alcohol about to be drunk, and is excellent when washed down with Brennvin (a strong local spirit made with herbs) straight from the freezer. The girls suggest that the best place to look for shark is in a shop, rather than on a restaurant menu, and recommend buying the white cuts of meat because they are not as tough as the brown-tinged ones.
Eventually, I unearth some plastic tubfuls in the 10-11 (the Icelandic equivalent of a 7-11). It is cut into bite-sized cubes that float in a pungent-smelling transparent liquid. The shark tastes like very fine Gorgonzola - at first. As I slide my teeth through the soft flesh, it becomes rather more fishy and a chemical taste whacks the back of my throat. I'm ashamed to say that I gag. But I do finish it. Perhaps you have to have Norse blood in your veins to appreciate it. Certainly, none of the clubbing British I speak to is able to say they enjoy it.
Yet there is one traditional Icelandic food that everyone likes and, indeed, that may soon be on its way to Britain - smoked lamb. I eat it on blackened flatbread as a mid-morning snack. It is perfect Germolene- pink, slicked over with the thinnest layer of fat. Maria Imgibergsdottir, an assistant at the Osta Budin delicatessen on Skolavordustigur, explains that lamb is usually cooked after being smoked over a fire made of wood and sheep's (here she gestures, waggles her half-mast Icelandic fringe, squirms in the backless trainers that would not be out of place in the trendier parts of London and finally whispers the word in embarrassment) "shit". In the newer, large-scale factories, she adds, making fires of sheep dung isn't practical and leaves are often used in its place. Icelandic lamb is famously good, and the smoked version (lamb had to be smoked to preserve it after the autumn slaughtering) is, I must say, truly delicious. It isn't exported from Iceland but we may soon be making it here.
At the end of this month Magnus Magnusson is to speak at a sheep conference in Shetland, and he hopes to persuade them to make smoked lamb for a niche market. "Farming is in such a mess they need to find niche markets," he says. So lamb smoked over sheep dung could soon be on our menus, though we may have a longer wait before we see British farmers burying sharks in their backyards.