The desire for the UK to be more self-reliant is a bad idea.

Today’s the day when the food runs out - or it would, if we had to rely on homegrown food. Launching a charter to get government, retailers, restaurateurs and shoppers to support UK farming, the National Farmers Union (NFU) declared: ‘Starkly, our current self-sufficiency rate means today, August 14, is the day British food supplies would run out if everything produced in a year was stored and eaten from January 1.’ The NFU says UK farms produce just 62 per cent of the food we eat.

So what? We now live in a global economy where we trade goods and services between countries for mutual benefit. If we can produce high-value products and sell them on the world market and buy the food we want more cheaply overseas, then we will be better off than trying to grow food in less-than-ideal conditions ourselves. Let New Zealand produce the lamb and Spain produce the tomatoes. In return, we will sell them Adele and One Direction (and some more sophisticated stuff, too). This is the idea of ‘comparative advantage’ first identified by David Ricardo 200 years ago and it still makes sense today.

The NFU campaign is attempting to use the notion of ‘food security’ to scare us into buying British. But what’s so secure about that? We can be thankful that when the fields of Britain were knee-deep in water over the past couple of summers, we had the world market to turn to. Even worse is the same idea with an environmentalist twist - that we need to cut down on ‘food miles’ or hunker down to eat only ‘local’ food. Locavorism is not only expensive and parochial, it doesn’t make sense in green terms, either.

As it happens, a significant proportion of UK imports are from elsewhere in the EU. Unless we’re going to go to war with the Netherlands, France or Ireland any time soon, food security is not an issue. Nor is it one-way traffic: UK farmers sell plenty of food to the rest of the world, too.

The NFU is doing its members a disservice. Rather than banging on about food security and demanding subsidies and special treatment from government, retailers and consumers, it would be better served having a shakeout of often inefficient small farms and making greater economies of scale. British farming is often technologically advanced and highly productive. Specialist producers are often excellent, too. So why the scaremongering and myth-making about food security?

Food security: running away from the world, spiked