The metric system, known officially as Système International d’Unités, or the International System (SI), is a standardised scheme used the world over. Well, almost.

While the UK has supposedly adopted it, the truth is somewhat different. Over here, we’re very used to imperial units. These are not just different systems of measurement, they’re different languages.

Switching from one to the other is no simple task. Changing words and units on road signs is easy. The real obstacles involve turning our backs on centuries of literary tradition and culture, abandoning an element of our linguistic individuality and, perhaps most significantly, changing the way we think.

Let’s skip back to 1668 for some context. John Wilkins, later to become bishop of Chester, published one of the earliest predecessors of the modern SI when he wrote a proposal for a universal decimal system of measurement. Two years later a Frenchman, Gabriel Mouton, proposed much the same thing – albeit in more detail. The French more or less ran with the SI from then on, while the UK has struggled against its implementation.

For example, in 1790 the French proposed a cooperative adoption of metric to improve trade efficiency. The UK said no. In 1904 the House of Lords voted for compulsory change to a metric system, but the bill failed. The UK Metrication Board was established in 1968 … and abolished in 1979. In 1973, the UK entered the EEC and pledged to adopt it, but by 2009 the requirement to fix a date for conversion of road signs was withdrawn.

In summary, we invented it. And then the French stole it. So we abandoned it. And now we’re dragging the chain.

Our reluctance to adopt the SI is caused by more than mere obstinacy. It’s about more than politics and anti-French sentiment too. The real reasons are many and intertwined, but language is certainly one of the main threads.

For starters, our minds create links between language and the physical world. Over time these links become bridges that are difficult to remove, let alone reposition. If tell you I am 1.8 metres tall and weigh 80 kilograms, what image pops into your head? And can you immediately envisage whether I’m taller, shorter, heavier or lighter than you? If you’re British, it’ll probably take your brain a minute or two. But you’re not alone.

Linguistic relativity may offer a clue to all this. While academics continue to argue about the strength of the link between language and cognition, most of them at least agree that it exists.

In its simplest sense, this means that people who speak different languages perceive and think about the world in different ways. The “father” of linguistic relativity, Edward Sapir, put it like this in 1929: “We see and hear and experience largely as we do because the language habits of our community predispose certain choices of interpretation.”

If we accept this concept is valid, then in changing the language we use (from imperial to the SI), we must also relearn mental associations between words and the way we perceive the world around us.

Facebook Twitter Pinterest George Osborne celebrates cutting another penny off the price of just over half a litre. Photograph: WPA Pool/Getty Images

But before we start retraining our stubborn minds, we should ask ourselves: why bother? Well, the SI simply makes more sense. Everything is divisible by 10. The relationships between quantities and units are more logical – there is coherence among units and the objects this language describes. The original, basic units of the SI were taken from the natural world. The unit of length, the metre, was based on the dimensions of the Earth. The unit of mass, the kilogram, was based on the mass of water having a volume of one litre or one thousandth of a cubic metre. Finally, the SI is globally standardised and is the universal language of maths, science and the armed forces.

On the other hand, there are plenty of reasons why we should keep speaking imperial. For one thing, it’s more intuitive. An inch is about a thumb (in many languages the word for inch is interchangeable with that for thumb). And, of course, a foot … is about a foot.

Most importantly, though, the UK has historical, cultural and practical attachment to linguistic elements of imperial measurement. Would the Proclaimers have written a song about an epic 807.7km journey? Would 22.86cm Nails have rocked it in quite the same way? Shakespeare also has a lot to answer for – phrases like “pound of flesh” and “not budge an inch” have etched their way into our language forever.

The UK’s particular position in relation to the SI seems to encourage nothing but questions. Is it a result of inherent cognitive function, plain old indecision or proud independence? And where to from here? Must we go one way or the other?

To be honest I don’t know the answers. However, if we all learned to speak SI, some things would be made easier. But in doing so, we’d eliminate another of our precious linguistic peculiarities. We’d make the world a more boring place. Most importantly, we’d be erasing an element of our individuality.

Our position (stuck stubbornly somewhere between imperial and metric) is more than a measure of units. It’s a measure of our place in the world – of tradition, independence and pints, not millilitres, at the pub.

Sam O’Flaherty is a copywriter at Barnaby Benson Copywriting. He’s also a Kiwi who’s been living in London for long enough now to think he can use the first person plural when talking about the UK.