You’re all set — your bags were packed long ago, there’s a dozen solid gold coins stashed inside your belt and a pistol strapped round your waist.

There’s no need to say goodbye to the wife and children as they’re already waiting for you 6,000 miles away in New Zealand, having slipped off quietly at the first whiff of global catastrophe.

Now, they’re making themselves comfortable in that fortress home you’ve spent years preparing. They’ve got store-loads of food and enough guns and ammunition to start World War III – which might, anyway, have begun by the time you arrive.

New Zealand - thousands of miles away from North Korea, ISIS and all the social tensions in Europe and the United States - is seen as the ideal 'safe' place for billionaires

The high-powered motorbike you’ve never used is waiting outside to whisk you to the private airport where your plane sits waiting.

A helicopter-ride at the other end, pull up the drawbridge — yes, you have one — and you’re ready to wait, for years if necessary, for civilisation to return.

Never mind the warnings about stocking up on vegetables after awful weather has ravaged the Mediterranean farming belt. Some of America’s richest people are spending billions quietly preparing for a global Apocalypse.

The world of Doomsday survivalists or ‘Preppers’ — those preparing themselves for total social collapse — is usually associated with wild-eyed eco-beardies hiding in the woods.

Nuclear war is just one of the fears driving the billionaire 'refugees'

But the existence of a very different group of Preppers was laid bare by a political row in New Zealand this week.

Attracted by a remote First World country that has the potential to be self-sufficient and is on no one’s list of nuclear targets, the super-rich kings of Silicon Valley and Wall Street are buying up vast tracts of its land — in anticipation of the day when they may need to live there.

The controversy has revealed the extraordinary precautions being taken by the mega- rich to ensure that WTSHTF — a crude survivalist acronym for ‘when the **** hits the fan’ — they and their loved ones will be safe and comfortable.

What the catastrophe will precisely be remains unclear, but possibilities include a devastating asteroid impact, giant earthquake, nuclear war, civil war, pandemic, zombie invasion and the Second Coming.

Tellingly, the geeks of Silicon Valley appear to be most worried that it will be a struggle between rich and poor in a world economy turned upside down by new technology — with them as the main targets.

The row in New Zealand involves scores of mega-rich Americans but has specifically centred on Peter Thiel, the billionaire founder of the internet payment system PayPal and an early investor in Facebook.

Thiel, a libertarian supporter of Donald Trump, paid $10million for a 477-acre lakeside estate in the country’s beautiful but isolated Southern Alps, which provided much of the staggering landscape in the Lord Of the Rings and Hobbit films.

Amid a public outcry over the invasion of U.S. internet and finance billionaires, the New Zealand government has released papers detailing the ‘exceptional circumstances’ under which the American tycoon was quietly given a New Zealand passport.

Peter Thiel (pictured, centre) is a big supporter of Donald Trump but he has an insurance plan if it all goes pear-shaped, having bought a 477-acre estate in New Zealand

It is difficult to understand how this complied with the rules, including one that insists foreigners must live there for three years beforehand.

Mr Thiel has gushed about his ‘great pride’ in his new citizenship and how he has ‘found no other country that aligns more with my view of the future’.

Perhaps what he really meant was exposed, after one of his Silicon Valley chums, the venture capitalist Sam Altman, revealed that, at the first sign of global disaster, he and Thiel would fly to New Zealand.

Other uber-rich Americans who have recently bought homes there include the billionaire hedge-fund pioneer Julian Robertson and the Hollywood film director James Cameron.

Local estate agents say their U.S. clients rarely intend to live in New Zealand, but cite reasons for their purchases such as the toxic presidential election and the spate of mass shootings in America.

In the first ten months of last year, foreigners — mainly Australians and Americans — bought nearly 1,400 square miles of land there, more than four times what they bought in the same period the previous year.

When they’re not buying up land abroad (Chile is also popular as it has low taxes, a good climate and good air links), rich survivalists like to swap tips on private Facebook groups or at regular dinners.

Popular subjects range from buying internet currencies such as Bitcoin, as protection against a central banking meltdown, to which foreign countries are most likely to hand them a passport and so the chance to relocate there in a crisis.

Some have planned for every eventuality. Steve Huffman, the 33-year-old co-founder of the internet discussion forum Reddit, which is valued at $600 million, is one of several Silicon Valley barons who has had laser surgery to correct poor eyesight.

If society collapses, he reasons perversely, getting hold of new spectacles might be a challenge. Ammunition could run out, too.

Steve Huffman (left), co-founder of Reddit, has had laser surgery because he does not want to rely on post-apocalyptic opticians, while Oracle founder Larry Ellison (right) is readying an escape hatch in Hawaii

Marvin Liao, a former senior executive at web giant Yahoo, has taken classes in archery and has amassed a small arsenal of other non-firearm weapons to protect his wife and daughter.

Survivalists have their own set of acronyms, including WROL (Without Rule Of Law) and LIA (Little Ice Age). (Some of them worry that the latter has just started).

They also have secret buzzphrases. ‘Saying you’re “buying a house in New Zealand” is kind of a wink, wink — say no more,’ Reid Hoffman, a venture capitalist told the New Yorker magazine.

‘Once you’ve done the Masonic handshake, they’ll be, like: “Oh, you know, I have a broker who sells old ICBM [intercontinental ballistic missile] silos, and they’re nuclear-hardened, and they kind of look like they would be interesting to live in.” ’

These brothers in paranoia don’t necessarily agree on how to survive the approaching cataclysm. Antonio Garcia Martinez, a former Facebook product manager, bought five wooded acres on an island off America’s north Pacific coast.

For this refuge, he brought in solar panels, power generators and thousands of rounds of ammunition.

He chose the spot because it’s far from cities — but not completely remote, as ‘one guy alone’ couldn’t hope to stand up to a ‘roving mob’. One would need to set up a ‘local militia’ with others, he says. And when you have your hundred or so acres of land, what do you put there?

Post-apocalypse design for the money-no-object brigade tends to involve creating a home with a huge bomb-proof basement. The home must be self-contained, not only ‘off the grid’ (with its own power and water supplies), but with tanks for raising tilapia — a hardy, fast-growing fish — to eat, and facilities in which to grow vegetables hydroponically without soil.

Naturally, property developers are eagerly capitalising on such concerns. The Survival Condo Project, a former underground nuclear missile silo in Kansas, has been converted into a 15- storey luxury apartment complex with a pool, gym, classroom and a miniature hospital.

It also has ground-level security cameras, electric fences, an on-site armoury, a sniper post and even a prison cell in which to put unwanted visitors. Instead of windows, giant LED screens show live pictures of the prairie above.

Its creators, who’ve sold all 14 of the $3m homes and are developing a string of new sites, say it can sustain 70 people indefinitely. That is, as long as they can put up with living in what a visitor compared to a well-furnished submarine — silent and rather oppressive.

Project boss Larry Hall says he gets more phone inquiries every time North Korea tests a bomb.

His team promise to send a Pit-Bull VX armoured truck to collect a resident from within a 400-mile radius of the silo.

Others prefer to put their own plans in place. Reddit founder Huffman says he realised a motorbike would be a necessity after watching the disaster film Deep Impact, in which people try to flee a tsunami caused by a comet-strike, clogging the streets so cars are brought to a standstill.

All this panic among the super-rich begs an obvious question: what do they know that the rest of us don’t?

Certainly, preparing for the Apocalypse has been a multi-billion dollar business for many years.

Polls have shown around 22 per cent of Americans believe the world will ‘end’ in their lifetime. Many right-wingers were convinced that Barack Obama would start a civil war by trying to seize citizens’ guns.

Now, there’s the unpredictable Donald Trump to disturb their dreams. More than 13,000 Americans registered to buy a home in New Zealand — 17 times the usual rate — in the week after he was elected president.

There are TV shows about so-called preppers, a survivalist radio network and disaster readiness conventions. There are estate agents dedicated to the task, scouting out easily defendable properties, and even ‘Doomsday dating’ sites such as Survivalist Singles (motto: ‘You don’t have to face the future alone’).

But why are the country’s most privileged people, protected by immense wealth, quite so in fear?

For it is believed that at least 50 per cent of Silicon Valley billionaires have taken out so-called ‘apocalypse insurance’ by finding a refuge at home or abroad. Reluctant to admit the truth, they often describe it as a holiday home, so it’s difficult to know whether or not Facebook founder Mark Zuckerberg bought a 750-acre estate in Hawaii ‘just in case’.

Similarly, his fellow tech billionaire Larry Ellison, founder of Oracle, who has not only bought 98 per cent of Hawaii’s sixth largest island, Lanai, but — handily — its own airline.

Of course there is the possibility that these fretting tech wizards’ prescience is justified. For many have made their fortunes out of predicting mankind’s dependence on digital gadgets and so we should respect their Doomsday hunches. Survivalists say the first signs of crisis often appear on internet chat forums, as they reportedly did before the 2008 financial crash.

Yishan Wong, another Silicon Valley multi-millionaire who has had eye surgery in readiness for a world without opticians, argues that techie types see risk in a clear-headed way. An apocalypse may be a remote possibility but, if you have money to burn, it’s ‘logical’ to take out insurance, he says.

A less flattering theory is that they’re simply bored nerds who long for adventure and fantasise about a future in which they’ll be a woman-magnet cross between apocalyptic hero Mad Max and environmentally friendly chef Hugh Fearnley-Whittingstall.

Romanian riot police detain a man after clashes erupted during a protest in Bucharest this week. But many fears the world is going to Hell in a handcart

A New York architect told me he was hired by a senior partner at the bank Goldman Sachs to build a post-Apocalypse house far outside the city. His client wanted it to be a rallying point for local people, gathering — of course — to fall into line under his leadership.

Certainly, Reddit founder Mr Huffman claims he’s ‘a pretty good leader’ who ‘will probably be in charge, or at least not a slave’ if civilisation falls to pieces.

For these great Silicon Valley egalitarians fear that if society collapses, vengeful mobs will look for the super-rich. And, in particular, for the tech wizards whose robots and artificial intelligence systems are taking humans’ jobs.

A critic might ask why, if they’re so alarmed by a battle between rich and poor, they don’t stop wasting their billions on stockpiling armouries and islands and spend it helping the less fortunate?

But then what sort of red-blooded tech king wants to sign a cheque to charity when they could splash out on helicopters, Ducati motorbikes and an assault rifle for every family member?

It’s easy to laugh at the obscenely rich finding grotesque new ways to waste their money. But it’s undeniably disconcerting when it’s the lords of our digital age.

After all, everyone in Silicon Valley claims they want to save the world, not run away from it.