Boris Johnson spent a week visiting Japan, New Zealand and Australia in the pursuit of post-Brexit trade deals. Instead the gaffe-prone diplomat ended up riling a far bigger economy: China. Known back home just as ‘Boris,’ Johnson is a popular figure often tipped as a future prime minister while he serves as foreign minister. He played a key role in changing the tide of public opinion in favor of the U.K. leaving the European Union. In his official capacity, he’s been charged with charming nations and convincing them of the value of strengthening commercial ties with the U.K. even as it prepares to quit the biggest trading bloc of them all. The problem is that his rhetoric often lands him in trouble. In a speech in Sydney on Thursday, Johnson urged all countries bordering the South China Sea “to respect freedom of navigation and international law.” That sounded the alarm back in China, arguably the one economy Britain can ill-afford to peeve given the political sensitivities in play. Britain “is ready once again to articulate our commitment to international order with money and a military presence,” he said, adding “that is why one of the first missions of our two vast new aircraft carriers will be to sail through the Straits of Malacca.” Making Waves While Johnson didn’t point the finger at China directly, his comments were interpreted as an indelicate reference to overlapping territorial claims in the region by countries including China, Taiwan, the Philippines and Vietnam. China claims most of the South China Sea, one of the world’s busiest shipping routes, and in recent years it has boosted its military presence, reclaiming thousands of acres of land to build artificial outposts on reefs. The Strait of Malacca is the gateway to the South China Sea and the Pacific Ocean from the Indian Ocean. “There are no longer any British colonies in East Asia and the presence of Britain’s warship in the region is more like an aberration,” China’s Global Times said on Friday in an editorial. “Brexit is weakening Britain’s influence, and it appears that the country needs to do something to assert its sense of identity. If it goes too far, however, it will get itself in trouble.” While the Global Times isn’t a Chinese government publication, it’s affiliated with the ruling Communist Party and is often used as a mouthpiece for government thinking. The government’s official response was more measured. ‘Tranquil’ Sea “An individual nation that is not in the region insists on making some waves in the South China Sea where it has turned tranquil,” the Chinese Foreign Ministry said in a statement. “China is sincere in creating a golden era in China-U.K. relations, but it requires efforts from both sides to improve any bilateral relationships.”  The economics of keeping China happy are compelling. It was the seventh-biggest destination for British exports in 2017, and the second-biggest outside Europe, buying more than 13 billion pounds ($17 billion) worth of goods in 2016, according to U.K. statistics. It was also the third biggest source of imports, with Britain buying some 36 billion pounds worth of goods. China’s importance was not completely lost on Johnson, though. “We will be here as a partner and friend, aiming at good relations with all the major countries of this region—not choosing between them,” he said. “Our relationship with China, the engine of global growth, will be crucial now and in the future.”