By Mohamed A. El-Erian

England suffered a very public humiliation last week when it exited early from the World Cup, and with other parts of the U.K. failing to qualify for the tournament it's easy to forget that Britain punches above its economic, financial and political weight in most regional and global forums.

Understanding why England still enjoys such outsize influence is useful to consider, especially now that the U.K. itself is facing internal pressures to turn inward and become more insular and less united.

Undoubtedly, the British start with structural advantages when they engage overseas. Their language is the one most commonly used in international forums; English has even become the sole working language of many private and public Asian and European-based institutions. And then there is the international status of London, a financial, cultural and political nexus that attracts many foreign visitors and residents.

Yet this does not really explain Britain’s disproportionate influence. I think one of the better reasons is the country’s ability to continue to exploit its historical legacy. As one of the world's first truly global superpowers, Britain has vast experience assessing and internalizing what goes on elsewhere; the British are among the best, if not the best, at taking advantage of the world's interconnectedness.

Strong historical links to other countries and modern diplomatic agility are supported by an excellent career civil service that — unlike its counterpart in the U.S. and elsewhere — also enjoys the strength that comes with continuity. This is the same civil service that has the magical ability to draft the minutes of diplomatic meetings before the meetings actually take place, giving Britain a distinct advantage in shaping policy discussions.

All this has served Britain extremely well over many years. Yet internal forces are now challenging England's impressive global-mindedness by favoring less regional, international and even national engagement — the result of Britain’s domestic politics turning more insular and more fragmented.

The last few years have witnessed the emergence of the U.K. Independence Party, a political force that is eager for Britain to disengage from Europe and become a lot less international (this, despite its support for free trade). UKIP's success at the recent elections for the European Parliament should not be casually dismissed.

Meanwhile, Prime Minister David Cameron’s decision to hold a European Union referendum after Britain’s next parliamentary elections will keep England's stance toward Europe in very active political and media play. At the same time, the government's public effort to block Jean-Claude Juncker’s appointment as the next president of the European Commission places its national prestige on the line in a battle that it is likely to lose.

There are internal challenges, too. Britain must navigate a September referendum on Scottish independence. Although polls suggest that the Scots are unlikely to secede, it would be foolish for the British to discount an electoral surprise on an issue that involves such deep emotional and historical connotations. A U.K. without Scotland would likely be less potent regionally and globally.

Few in Britain welcome the early return of England’s World Cup squad, but it's an occasion for reflecting on a bigger and more consequential issue. The U.K.’s global heft has served its citizens well in terms of trade, income and economic growth. A country that has benefited from all of that would be shortsighted to turn its back on the world by embracing excessive insularism and nationalism.