The apocalypse is upon us. Again. On December 21, the Mayan calendar comes to an end, which some believe means that the world will end on that day. Or it could just mean that the Mayans' 2013 calendar was held up at the printers. Guatemala, where the ancient tribesmen did much of their astronomical calculating, is enjoying a rare tourist boom, with President Otto Perez Molina advising visitors to "enjoy yourselves, but be careful".
That's the way to go. Most scientists express doubt that the world will end on Friday and warn that anyone expecting it to will be pleasantly disappointed. The whole scare, according to Mayan scholars, is the result of a common misunderstanding of how the calendar worked. Time was treated by the Mayans as a series of cycles, with each phase ending to be replaced by another. The conclusion of a cycle means only that a new one is beginning, but that hasn't stopped the December 21 date being seized upon by doomsday-prophecy authors, movie producers and assorted internet loonies - to the extent that a man in China has spent his life savings on building an 80-ton ark.
Even so, the apocalypse has to be out there somewhere. The big questions are when it will come and what it will look like. Among the current popular scenarios are global plague, an asteroid strike, a geo-magnetic reversal of the Earth's poles, nuclear war, being swallowed up by a black hole, alien invasion, overpopulation, climate change, and - particularly hot on the internet - a killer zombie virus. Or it may simply be that the world will end when Simon Cowell says so.
In the meantime, it is wise to take precautions. Suppliers of survivalist equipment say there has been a huge upsurge in demand in recent months, with items such as anti-contamination suits and tinned bread being especially popular. With a Reuters poll last week showing that 10% of the world's population believe that the Mayan "curse" will come true (rising to almost 25% in the United States), other nations are understandably looking to the British to set a stiff upper-lipped example of how to face the end of the world.
The important thing is to stay calm, don't panic, and paste our list of "dos" and "do nots" to the barricades around your front door.
What to wear
In Hollywood disaster movies, those cool, post-apocalyptic landscapes of charred trees, drifting smoke and skyscrapers with all the windows blown out provide a particularly attractive background for men in shiny motorbike leathers. In reality, this kind of outfit is a bad idea. Much better is to remember your old mum's advice and "dress in layers". Lots of them. Shelter will be hard to find, and if germs or radiation are in the air, it pays to be well-swaddled.
Do: Pack goggles, gloves and a set of "Blast Boxers" shock-wave-absorbing underwear for men and women.
Don't: Wear anything you may have looted from Primark.
Where to be
There are few reliable bolt-holes in an apocalypse, but some places are safer than others. A favourite destination for the Mayan panic is Sirince, a small town in western Turkey, which, according to New Age lore, will be spared from destruction by the "good energy" emanating from the nearby ancient city of Ephesus. Similarly popular is Bugarach, a village in the French Pyrenees, which will apparently be saved because it sits on a mountain that looks like the alien landing site in Close Encounters of the Third Kind. The mayor, Jean-Pierre Delord, says: "It's like a zoo here. Everyone's coming."
Do: Book a place in a purpose-built bunker. Rates are as low as pounds 10-a-night, including wine and bread.
Don't: Stay at home. Unless it's a cave. Experts say the minimum thickness required to resist radiation or bacterial penetration is 16 inches of solid stone, brick or concrete.
Remember all those girls who said they wouldn't sleep with you if you were the last man on Earth? Well, now it's time to find out if they meant it. Snagging a date may not be your post-apocalyptic priority, but the ultimate duty of the survivors will be to re-populate the planet. Depending on how many of us are left, experts say this could take several hundred years. The sooner we get going the better - and to start things off, a company in Los Angeles is selling 1,200 places in a "porn bunker" that comes with a cocktail bar, pole-dancing and soundproof boudoirs.
Do say: "It wouldn't be the end of the world if you got pregnant."
Don't say: "You look so cute with all your skin eaten off."
As a meteorite the size of Greenland hurtles towards the Earth, the world's leaders will be expected not only to find a solution, but also to prevent panic. The early signs of their ability to handle this are not good. Last week Australian premier Julia Gillard made a supposedly satirical television address to the nation, saying: "My dear fellow remaining Australians. The end of the world is coming. It wasn't Y2K. It wasn't even the carbon price. It turns out that the Mayan calendar is true." Strewth, Bruce, I haven't been so scared since the fridge door jammed.
In Moscow, Russia's "Minister for Emergency Situations" is warning that hoarders will be jailed; while the Pope's chief Vatican astronomer, Fr Jose Funes, suggested last week that even to talk of an apocalypse was un-Christian, saying: "Death can never have the last word."
Do: Ask the next doorstep canvasser where his party stands on the zombie containment issue.
Don't: Enquire if your MP is claiming the Whitehall bunker as a second home.
So the apocalypse has finally happened, and with all money now worthless, a survivor suddenly has to figure out how many cans of baked beans a water purification kit costs. The world has gone back to an early civilisational barter system, and as in the Mad Max movies, certain things are worth a lot more than you ever thought they were.
Survivalists routinely recommend stocking up on cigarettes, chocolate, soap, dried food and fuel. For longer-term thinkers, though, the smart choices are seeds and how-to guides to skills such as agriculture and construction. Remember the nuclear winter starts to thaw after four years.
Do say: "Have you got change for a can opener."
Don't say: "Could anyone lend me a goat until payday?"