IF THE past four of five years of events at home and abroad can teach us one thing alone, it should be that we live in a house of cards built on a windy beach.

Nassim Nicholas Taleb wrote about freak occurrences which seem obvious with the benefit of hindsight, but nobody saw them coming. He called them Black Swan events.

His argument was that we should try to prepare for them because although they are very rare, they have a huge effect when they do happen. It seems to me that we are on the edge of a Black Swan event right now.

And yet, despite all the political torment of the past five years, the British economy creaks on, looking a tad shaky I grant you, especially if you are involved in our industry, but still just about intact. Unemployment is at a record low.

It is easy to argue that Nirvana is within our clutches if we would only grasp it to our bosom and take the final leap into a no deal Brexit.

The Boris mantra is 'do or die', an unfortunate and ironic choice of phrase, adapted as it is from Tennyson’s Charge of the Light Brigade. One hopes Mr Johnson doesn’t expect us to ride into the Valley of Death for him.

So, everything is absolutely fine right up to the moment when suddenly it really isn’t any more. Discontent will simmer under the surface indefinitely, a powder keg ready to blow, but more often than not it takes the spark of food shortage, or rising prices to set things ablaze.

It is a common theme through the ages. Rome doled out grain gratis to its population to stave off regular food riots. The French Revolution in 1789 was famously sparked off by bread shortages following a very dry year in 1788.

Less well known, perhaps, but closer to home, is the effect of famine in Scotland in the 1690s when the coldest decade of the Little Ice Age led to a series of disastrous harvests. Between five and 15% of the population starved to death.

In Aberdeenshire, the loss of life was estimated to be as high as 25%. Up to 100,000 Protestant Scots emigrated to Northern Ireland, the effects of which reverberate to this day.

The Bank of Scotland and The Company of Scotland Trading to Africa and the Indies was set up as a response. In an attempt to turn things around quickly, The Company of Scotland blew what was left of the nation’s money on the disastrous Darien Scheme in Panama, leading directly to the Union of Scotland with England.

Food riots are not something we are familiar with in recent times in this country, but they happen all the time elsewhere on the planet. The Arab Spring in 2011 would never have happened without massive food price inflation in Tunisia. Sure, there were a lot of other factors, but nothing motivates mass protest like hunger.

So, Tunisia rose, then unrest spread to Libya, Egypt, Yemen, Syria and Bahrain, toppling governments and spreading death and destruction. The image of millions fleeing Syria for Europe was shamefully used by Farage et al (remember that disgraceful poster?) and was probably the tipping point for Brexit.

People will put up with most things, particularly in Scotland. Whilst England riots every decade or so, Scotland is a relative model of restraint – at least when it comes to organized violence on a large scale.

I’m not trying to be smug, but we didn’t kick off in the same way over the Poll Tax, or race, or police violence, or austerity. There was no widespread civil unrest during the independence referendum, despite some unseemly incidents.

We only riot, roughly, once a century, and it’s 100 years since our last big one, the 1919 Battle of George Square, in Glasgow, between police and striking workers.

So, the first and foremost duty of a government should be to secure a safe and affordable food supply for its people. Unfortunately, a couple of self-inflicted problems might stand in the way of that.

Firstly, there is climate change. A study by the University of New South Wales in Australia, published in Environmental Research Letters, has identified global hotspots that are disproportionately affected by extremes of temperature.

"We found that most of these hotspots – regions that are critical for overall production and at the same time strongly influenced by climate variability and climate extremes – appear to be in industrialised crop production regions, such as North America and Europe.”

For climate extremes specifically, the researchers identified North America for soya and spring wheat production, Europe for spring wheat and Asia for rice and maize production as hotspots, according to an article in PhysOrg.

Secondly, most financial analysts predict the pound falling to parity with the euro in the event of a no deal Brexit in October. This would have a catastrophic effect on the willingness of our Eastern European friends to come over and work in the UK harvesting fruit and veg. We are already in competition with the rest of Western Europe for their services and this would be the tipping point for them to go elsewhere unless we are able to pay them more and pass the cost on to the consumer.

Without them, there is no UK horticulture and no home-grown fruit and veg. The SAWS trial scheme for non-EU workers cannot possibly be ramped up to the numbers required in time for 2020 and in any case, under current rules it costs an extra £430 per worker compared to employing workers from the EU.

Of course, the government could decide to bring in more imports from abroad and you can be pretty sure that, with all those free marketeers in the Cabinet, some of them think this is a good idea. However, with the pound being weaker and climate having an impact on harvests, these imports will no longer be cheap, and they certainly won’t be subject to the same rules on pesticide use and animal welfare.

Whatever happens, food is going to become a lot more expensive and British horticulture won’t be the beneficiary.

The long period of stable food supply that we have come to take for granted might be coming to an end and wise governments will take steps to secure a higher percentage of food production within their own borders.

There are a lot of 'ifs' between now and October, not least the likelihood of a general election in September when the PM fails to get his fabled new deal. However, as the Kaiser Chiefs might put it, if this government goes ahead with a no deal Brexit in October, 'I predict a riot.'