It’s all very well for secretary of state for the environment, farming and rural affairs Therese Coffey to suggest that we replace the tomatoes on our pizzas with turnips (and in one sense she makes a valid point about eating seasonal food), but her rather flippant comment doesn’t cover up an uncomfortable truth: years of bad (or indeed non-existent) food policy has resulted in Britain no longer enjoying food security.

Yawning gaps in our supermarkets’ fruit and vegetable aisles are not just about a lack of salad supplies.

They reveal a rather more serious situation in which our country is increasingly unable to guarantee being able to feed itself.

It’s easy to look for a simple explanation for the current crisis: bad weather in Spain and Morocco, or Brexit.  These are both definitely factors (more on that in a moment), but the underlying problem is that as a country we don’t take the ability to put food on our plates anywhere near seriously enough.

Let’s start by looking at the short-term factors which have exacerbated the situation.

First, the crop in Spain and Morocco has been affected by unhelpful weather.  But this alone cannot explain why our shelves are bare.  

After all, everywhere else in Europe has plenty of supplies, it is only here in the UK that our supermarkets are looking like a 1970s Soviet state store.

So, is it Brexit?  Well, yes and no.  Brexit certainly hasn’t helped.  

When supplies are low, which countries do you think will be at the front of the queue for tomatoes?  Those which are easy to export to, with no tariffs, trade barriers or excess bureaucracy?  Of the country which has – of our own choice – made it difficult for hauliers to bring in supplies?

Last week we heard that there are actually plenty of tomatoes in the Netherlands, but they can’t find any lorry drivers willing to bring them to the UK.  

And who shall blame the drivers?  Who wants to immerse themselves in a Kafka-esque morass of paperwork, delays and extra costs when there are 26 other countries on their doorstep where trade is completely frictionless?

So Brexit has certainly made the situation worse, but it is not the primary reason that our shelves are bare.

The main problem is that years of inaction on the part of government, which has been happy to leave feeding Britain to the supermarkets, has led to a situation where the slightest disruption can bring the whole system down.

The rigid contracts laid down by the supermarkets on producers leave little room for manoeuvre when things go wrong.  

So in the current situation, the wafer-thin profit margins offered by the retail giants have meant that many UK growers – faced with soaring energy costs – have simply decided not to turn the heaters on in their glasshouses this winter.  

They lose less money leaving them empty of crops than they do trying to produce food for which they won’t get paid even the cost of production.

The combination of changing climate, conflict in one of Europe’s biggest food producing countries, massive increases in the cost of growing crops, and the spectacular own goal that is Brexit, has led us to a situation where one of the richest nations on earth (although not for long – we are about to be overtaken by Poland) cannot guarantee that it will have enough food in its shops to feed its citizens.

This is a crisis which has been brewing for a very long time – since way before Ukraine war, way before the EU referendum, way before climate change started to have a real and tangible effect on our ability to produce food.

Security should always be any government’s first priority.  But security doesn’t just mean defence, or counter-terrorism, or fighting crime.  It also means food security.  

For too long politicians have been obsessed with letting ‘the market’ sort out almost every problem.  The issue is that ‘the market’ has, as most experts predicted, failed.

We are not yet starving; not having salad items is hardly a life-or-death situation.  But the current shortages are symptomatic of a much more fundamental issue, which if we ignore for much longer will lead to genuine hunger.  

We have to shift the balance of power away from supermarkets and back towards farmers and food producers, and government has to start seriously supporting those farmers and producers.  

That may stick in their dogma-driven free-market craws.  

But it’s a matter of national security, and that should outweigh any ideological considerations.