In all the talk about Brexit, there is one line of thinking that keeps emerging. Given that our trade relations with the European Union will be substantially altered in the very near future, and given that those with the rest of the world have been filtered through the prism of EU membership since 1973, shouldn't we urgently be seeking to forge new relationships on our own behalf?

Of course North America, Asia and the Middle East spring to mind as key players in the global marketplace, but there is perhaps one international association that has been overlooked for decades. Step forward, the Commonwealth.

Here in Gibraltar, our government sent out a powerful signal with a recent announcement. Currently, three flags – the Flag of Gibraltar, the Union Jack and the Flag of the European Union – are flown at important public spaces, including the frontier with Spain, at the top of The Rock and on the Parliament Building. When we formally leave the EU, the latter banner will be replaced with the Flag of the Commonwealth of Nations. I thought it might therefore be appropriate to delve a little deeper into this Commonwealth.

The public perception presents a challenge. Many people consider the Commonwealth to be outdated at best and a relic of imperialism at worst – an attempt to cling on to a vision of long lost imperial greatness that no longer holds any relevance in the 21st Century. Many of these former dominions, colonies, protectorates, mandates and other territories have been independent for decades and few people alive today can claim to remember the British Empire at its zenith. I don't agree. Just ask the citizens of Cameroon, Mozambique and Rwanda. Confused? Read on.

By way of context, I developed a fascination for the Commonwealth as a small child having been introduced – as many of my generation were – to stamp collecting. For me, this interest turned into an obsession and, because it's summer and hopefully fewer of my acquaintances are at large on the Rock, I can seize the opportunity to come out of the philatelic closet and admit that my infatuation persists today; indeed I was recently "outed" in the office when my monthly copy of The Stamp Magazine arrived. The Commonwealth is a favourite theme for many philatelists, and so it is with me.

Before considering the trade opportunities, perhaps we should clear up some misconceptions. The organisation is not, please, the "British Commonwealth". Granted most (but not all) of the member countries were once part of the British Empire, HM The Queen is head of the organisation, and it is headquartered in London – but it is formally known as the Commonwealth of Nations and its stated aims are to promote development, democracy and peace. And for development, read business. Hence my decision to focus on this intriguing bloc in this month's column.

International business is all about communication and language is a good place to start. One of the key advantages of the Commonwealth nations is that, with just one or two exceptions, English is spoken – if not as their mother tongue then as an official language. Consider India, by far its largest member, which has 122 major (spoken by more than 10,000 people) languages and innumerable dialects. English, along with Hindi, is one of the two languages permitted in the Constitution of India for business in Parliament and has emerged as a de facto lingua franca over much of the country.

And there is more, much more. Most Commonwealth members have adopted legal frameworks based on the English system – a good example perhaps of common law (pun intended). Most of the members are also governed using a "Westminster" model, generally with elected parliaments and a separate head of state. In the case of 16 members – known as "commonwealth realms" – HM The Queen is actually the monarch.

If we share common law, common language, common institutions and common parliamentary structures, it is not difficult to see that this should also give us a de facto advantage in respect of trade. After all, the statistics concerning this group of otherwise disparate nations are staggering.

Today, the Commonwealth is made of up 52 independent countries that boast a combined population of almost 2.5 billion – put another way, one in every three people in the world lives in a Commonwealth country – and well over half this huge total is under the age of 30. It also includes 20% of the world's land area and spans all six inhabited Continents. Although almost half of the member countries are termed small island developing states, at the other end of the spectrum are established economies like Australia, Canada and New Zealand, and massive emerging markets such as India, Malaysia and South Africa. Malta and Cyprus, of course, are both Commonwealth and EU member states.

As Foreign Minister Boris Johnson recently pointed out the Commonwealth will soon overtake the EU in terms of the size of its economy. "It is a stunning fact that when the UK joined the Common Market back in 1973, the 28 countries then had about 38% of global GDP. The Commonwealth then was about a quarter of that," he said. "The EU and the Commonwealth in GDP, in output terms are now roughly level-pegging and the Commonwealth is growing far faster."

One easy way of determining whether a country is a member or not is to look at its representation in London (and vice versa for British diplomats abroad). If a High Commissioner is in place rather than an Ambassador you have your answer. This is because Ambassadors are exchanged between foreign countries; Commonwealth members crucially consider that they are not "foreign" to each other.

For international business, post-Brexit planning will become ever more important as Britain's future position in Europe becomes clear. We do not yet know – despite many assertions during the recent UK election campaign – what a reduced EU will look. It would be unwise to underestimate the massive gap that the UK's departure will mean. We can only hope that Brussels resists any pressure to adopt a "punitive stance" and that a future agreement will contain favourable trade provisions for doing business in and with Europe.

But we cannot just assume that. After all, every EU member state will be seeking to protect their own interests and new rules and regulations may be introduced to make life difficult for the UK. My suggestion therefore is to start looking now at the opportunities further afield and the Commonwealth penny may be about to drop. It may be a very sensible insurance policy. Although the Commonwealth does not have a multilateral trade agreement, research by the Royal Commonwealth Society has shown that trade with another Commonwealth member is up to 50% higher than with a non-member on average, with smaller and less wealthy states having a higher propensity to trade within the Commonwealth.

I have alluded a couple of times to the fact that most Commonwealth countries were once British territories and use English as their official tongue. But what about my earlier reference to Cameroon Mozambique and Rwanda. None of these countries was ever formally under the "British yoke" but they all elected to join the Commonwealth – the first two in 1995, with Rwanda following in 2009. They did so to benefit from being part of such a large, influential international club.

We are about to start bidding farewell to some of the closer EU bonds we currently enjoy and here in Gibraltar we do so reluctantly. But there is a much wider world out there. The Commonwealth is waiting. www.thecommonwealth.org is a great place to start.

What are you waiting for?

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