Xi Jinping doesn’t care about Britain. Should we care even less about him?

If anyone was looking for evidence of the muddle that is the UK’s China policy, it would be hard to find a more comprehensive illustration than the spying charges brought with great fanfare, then dropped just before the trial, against two men called Chris.

Christopher Cash, a parliamentary researcher at the time of his arrest, and Christopher Berry, a teacher formerly based in China, both pleaded not guilty and are now free to carry on their lives, though slurs cannot but endure.

To its credit, the Great British public is taking this hue and cry in its stride, perhaps because they see it for what it is: the latest round in a domestic argument about relations with China, which is quite remote from their day-to-day concerns. Government and politicians, on the other hand, remain seized of this spy saga, even after the three-week parliamentary recess. Why the disconnect?

Even when presented as the shock-horror scandal of two young(ish) Britons allegedly spying for China, this was never Kim Philby or Guy Burgess betraying the vital interests of Great Power Britain. China may loom large in the UK’s political consciousness, but Xi Jinping and the China he leads have many bigger fish to fry than medium-power Britain. This is not to say that China has little interest in trade deals or intelligence-gathering in Britain – it patently does – but the scale of that interest has to be seen in proportion. Think of the US, India, and the EU.

Some clarity as to the now-dropped charges against Cash and Berry has been afforded by this week’s release of the memos written by a deputy national security adviser, Matthew Collins. Still, there remains a degree of fuzziness about what might constitute espionage in these days of extensive open-source material. It is the job of parliamentary researchers, as it is of academics, journalists and diplomats, to sift conclusions from large amounts of information in the public domain.

At what point might this cross into spying or assisting a foreign or hostile power? At one level, the answer might be obvious: if it is labelled “top secret” or knowingly passed to someone likely to use it against the UK’s interests. But what if a Chinese – and by no means only a Chinese – official, say, simply knows where to look and how to interpret published insights into the workings of UK institutions? No legal line has been crossed. What if the researcher or diplomat tips off a foreign colleague or contact on where to find such information?

The speed with which anyone mentioned has sought to deflect the blame, from the Crown Prosecution Service to the usually reticent intelligence services, has been a wonder to behold. In the end, it appeared that the relatively lowly Matthew Collins was to be where the buck stopped. In a highly unusual and questionable move, his memos were released, even as they left open the question as to whether China was or was not to be regarded as an enemy.

Christopher Cash’s role as a parliamentary researcher only inflamed political passions further, with the Speaker, Sir Lindsay Hoyle, warning at length about the risks to the security of Parliament from powers such as China. This was followed by what would be described by many as an “unhelpful” intervention from Boris Johnson’s former aide, Dominic Cummings, alleging that China had been able to breach government security multiple times.

Yet still, it seems, public opinion cannot quite share the indignation of the politicians, which is hardly surprising, given the vagaries of the UK’s China policy. It is almost 10 years to the month since the then-chancellor, George Osborne, called for the “creation of a golden decade” in UK-China relations – an ambition abruptly reined back by Theresa May. She had barely entered Downing Street from the Home Office before voicing qualms about the degree to which Chinese money and expertise had become enmeshed in the UK’s vital interests, from nuclear power (Hinkley Point and Sizewell C), through telecoms (BT and Huawei), to research collaboration in UK universities.

A level of cooperation and dependence had been allowed to develop that would never have been allowed to, say, Russia, or indeed many other countries, but with China, because of its size and potential wealth, was judged to be in the UK’s interests. And if the complication of a spy trial has been seen off, another source of friction now looms in the form of China’s plans for a new mega-embassy on the site of the old Royal Mint opposite the Tower of London, which will inevitably be tied to UK plans for a new embassy in Beijing.

Above all, what this potential new row shows is the folly of defining one or other country as by nature an enemy. In the sentiment ascribed to Lord Palmerston, and repeated by Henry Kissinger, countries have no eternal allies and no perpetual enemies, only perpetual interests that it is their duty to follow. Repeating this a few times in recent weeks could have saved everyone, including the prime minister, a whole lot of bother.