A new reality is beginning to dawn on British policymakers. As Brexit Britain prepares to re-enter the international scene in more of a solo capacity — although of course still tied to numerous links of interdependence (perhaps more than ever) — the sheer size to which the China factor in world affairs has grown is challenging all the old assumptions.

Four decades or so ago, when Britain first joined the EU bloc, of course there were signs that the Chinese giant was stirring, although still very much keeping to itself on the world stage. The United States was the unquestioned superpower.

But since then it has been “all change.” The growth first in the Chinese economy and now in China’s world footprint has been earthshaking and defied every prediction.

In the past five years alone 30 percent of total world growth has come from China, vaulting it into second place in industrial size, (and likely to overtake the U.S. before long), becoming the world’s biggest energy player and now extending China’s reach and influence to every corner of the globe. In the words of the all-powerful Chinese leader, Xi Jinping, now elected for life, we are witnessing “a rise in China’s international influence, ability to inspire and power to shape.” China, he added, is becoming “a nation of innovators.”

The next five years could add at least 50 percent more to Chinese production, put China in the lead in many new technologies, bring another 100 million Chinese people or more into middle class standards from medieval poverty (on top of the 600 million who have already arrived), expand China’s trade and investment round the world exponentially, and greatly increase China’s weight in almost all aspects of geopolitics. One does not have to believe all the forecasts and claims to see that China is becoming the indispensable economic power, incidentally leaving Russia far behind.

All this demands a major and difficult shift of mindset in many countries, but nowhere more so than in Britain as it looks for new allies and new markets. This is because for Britain it was the U.S. that was always the bedrock, the founding partner in the postwar liberal order, by far the biggest investor in Britain and the biggest single country for British exports of goods and services.

So for British strategists to adjust to the prospect of another power of equal, or even greater, global importance was always going to be a wrench. Yet suddenly it becomes an urgent task to decide how to react and relate to the growing Chinese presence in every continent — for instance throughout the whole of Africa, in Latin America, the island states of the Caribbean and the South Pacific, the Middle East, Pakistan and Sri Lanka, across Central Asia as the Belt and Road strategy stretches out, and right into the heart of the European continent — and indeed deep into the British economy itself.

And there is a further challenge for Britain’s diplomats and national planners that complicates and compounds the difficulties. There is another precious relationship with a major Asian power to cherish and safeguard against Chinese involvement — namely its ties with Japan.

These are not minor. On the contrary Japan has long been seen as Britain’s “best friend” in Asia, just as Britain has been regarded as Japan’s best friend in Europe. And with good reason. Massive Japanese investment in Britain over 50 years helped transform the British economy. Nor has the connection been solely economic. Japanese-British cooperation on security and military affairs has been moving onto a new level of detail with officials from both sides in increasingly close contact.

So Britain confronts a tricky double dilemma and balancing act. Its interests and future are becoming more than ever bound up with Asia, and with the second- and third-largest, and most dynamic, economies in the world. Yet its whole traditional instinct and reflex have been to look first and foremost westwards to the American giant. As Prime Minister Tony Blair wrote unambiguously to U.S. President George W. Bush back in 2003, “We will be with you to the end.”

That was over Iraq, where the “end” turned out to be disastrously different from what the two leaders hoped and indeed remains elusive to this day. Despite all the American setbacks, and despite the extreme unpredictability of the Trump regime, over trade protection, over Iran and over the “fire and fury” handling of North Korea, and even over Russia, the bulk of British official opinion clings doggedly to what used to be called the special relationship, long after its nature has in reality changed radically.

But now along comes this even bigger new reality of China. How is Britain to measure up to that? Napoleon long ago warned that when China awoke it would shake the world. And the great British Prime Minister Benjamin Disraeli once proclaimed that Britain should become “an Asian power.”

Disraeli was of course referring to Britain’s Indian empire. But what happens when modern China and modern India start talking about getting together in partnership instead of pursuing endless disputes, as Chinese President Xi Xinping did with Indian Prime Minister Narendra Modi only a few days ago?

This is Asian power on a new scale, and for Britain the testing moment has arrived. Brexit may be a headache, but there is an entirely new agenda calling. The power, wealth and ubiquitous influence of China itself leaves Britain now no choice but to adjust its stance massively, for reasons of both prosperity and hard global strategy.

That needs a whole new government focus and a new parliamentary focus. Forty years of seeing the world through the EU prism has to be dismantled. Seventy-five years of looking almost exclusively to the U.S. for security has be unraveled. A cluster of EU-related committees in Parliament have to be re-directed. Government departments have to switch long-standing priorities. Maybe a new and powerful department is called for — an ultra-strong Ministry for Asian Affairs.

If that is where the future lies, that is where both Britain’s hard resources and its considerable soft diplomatic power must now be redeployed and targeted with the utmost concentration and effort.

David Howell is a British Conservative politician, journalist and economic consultant. He currently is serving as chairman of the House of Lords International Relations Committee.