Where’s the beef? Anyone looking at Theresa May’s three-day visit to China would be wise to focus on the substance: such trips have a history of over-promising and under-delivering. Yet it’s a sign of the times that the government has interpreted the question so literally, flagging up among its headline successes the possible lifting of a BSE-era ban so that British beef imports can reach Chinese tables. Overall, the package of agreements came in far short of previous visits. Though the mantra of a “golden era” of Sino-British relations was repeated, the shine has come off for both sides.

The trip, supposedly a declaration of Britain’s trade potential in the age of Brexit, was inevitably overshadowed by her own party’s wranglings over that very subject and her leadership. The relationship’s immense asymmetry has never been quite so stark. On one side, Xi Jinping, “chairman of everything”: the most powerful leader in decades of an increasingly mighty and self-confident (some say hubristic) nation. On the other, Mrs May, an enfeebled figure representing – but for how much longer? – a nation weakened and isolated by its own folly. Though we are assured she raised human rights and the parlous political situation in Hong Kong in her meetings, she did not do so publicly. A party-run tabloid even commended her for sidestepping the topic.

But there is no doubt that the prime minister’s tone on business was grittier and less compliant than that of George Osborne, who led the charge for Chinese cash, and David Cameron, who now leads the joint investment fund backing Beijing’s gargantuan Belt and Road initiative. She avoided an endorsement of the BRI infrastructure project, despite China’s blandishments. She raised intellectual property theft and steel-dumping.

Some of this reflects her lack of international vision, some a sensible caution. But another factor is that the wider mood has shifted as governments realise that China’s economic development will not translate to social and political alignment, as they once complacently assumed. Foreign businesses in China are increasingly unnerved by the pressures upon them. There is a growing focus on China’s use of “sharp power” to wield influence in Australia and New Zealand, and questions about its tactics elsewhere (such as among African Union members, given this week’s report – denied by Beijing – that China has been siphoning off vast amounts of intelligence from the $200m headquarters it built for the AU). Most of all, there is anxiety about China’s sheer confidence, fuelled by Donald Trump’s election and the Brexit vote. It is no longer biding its time but making increasingly bold statements about its place: proclaiming a new era, declaring its ambitions for “a new type of international relations” and lauding “the China Solution” to global travails.

Such developments not only give Britain pause for thought, but a concrete motivation to temper its enthusiasm, with an eye to its own relations with a China-hostile US administration and Europeans anxious about the BRI. Mrs May’s remarks on the BRI were similar to Emmanuel Macron’s; that they were more muted reflects her personal style, political status and most of all her lack of leverage – so powerfully demonstrated by the last few days. Liam Fox, the international trade secretary, admitted both that a free trade deal with Beijing is “some time away” and that Britain could increase bilateral trade without leaving the EU. Meanwhile, the leaked government analysis showing that the UK will be worse off under any Brexit scenario also showed how limited the scope is for losses to be offset by new trade deals, including one with China.

Now think on what terms such a deal might be reached. EU member states have failed to work together as effectively as they could in dealing with China, too often tempted to sell out their neighbour for short-term advantage. But Britain is self-evidently weaker as a solitary power, and less useful when no longer a gateway to the EU or a player in its decisions. It was wise of Mrs May not to approach Beijing as a supplicant. But in the age of Brexit, we look less like a fellow diner at the table and more like the contents of the plate.