Premier Li Keqiang of China, second only to President Xi, told the prime minister at the EU-Asia summit: “We are also happy to meet you, Madame Prime Minister, in Brussels. Indeed, your visit to China in January was a big success. We enjoy this golden era and usher in a diamond era.”

You may recall that during the now-forgotten premiership of David Cameron, an era that so feels so distant it may as well be that of Gladstone and Disraeli, the British liked to think of themselves building a “golden” age of Sino-British relations. Now it has been upgraded to diamond. Whatever next? Platinum? Frankincense and myrrh? Bitcoin?

He offered this paean to our embattled prime minister perhaps out of a sense of chivalry, or perhaps because he sniffs genuine opportunities in expanding China’s economic relationship with the UK.

Well, he might (and we might) try and remember two things while we observe this blossoming relationship.

First, that we are going to find ourselves growing politically and economically closer to an emerging superpower that has, shall we say, a mixed record on human rights at home and which has growing territorial ambitions abroad.

At home, every human rights observatory attests to the lack of freedom under the communist regime. They may be better or worse than others – or both – but the facts speak for themselves. Most recently they “disappeared” the head of Interpol, for heaven’s sake, much to the distress of his family. Whatever he may or may not have done wrong, there is no justification for this kind of imprisonment without trial. His wife claims that he is already dead. The international outrage is yet to be heard. No 10 so far silent. The contrast with the case of Jamal Khashoggi is striking.

High-profile as it is, it is hardly unusual. According to Amnesty International, Beijing has, over the past year or two, continued to draft and enact new laws under the guise of “national security” that presented serious threats to human rights. Nobel Peace Prize laureate Liu Xiaobo died in custody. Activists and human rights defenders were detained, prosecuted and sentenced on the basis of vague and overbroad charges such as “subverting state power” and “picking quarrels and provoking trouble”.

The case of laureate Liu Xiaobo was especially poignant, as he died in custody from liver cancer. According to Amnesty, the authorities had refused a request from Liu Xiaobo and his family that he travel abroad to receive medical treatment. At the end of the year, his wife Liu Xia remained under surveillance and illegal “house arrest” which had continued since Liu Xiaobo was awarded the Nobel Peace Prize in 2010. At least 10 activists were detained for holding memorials for him.

In November last year, writer and government critic Yang Tongyan, who had spent nearly half his life in detention, died shortly after his release on medical parole.

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There are serious allegations too surrounding China’s treatment of minorities. China has vociferously defended its human rights record at the United Nations after accusations were made that more than a million Uyghur Muslims have been imprisoned in political re-education camps. True, it is difficult to imagine human rights abuses being perpetrated on that scale, but there the accusations are.

So far, so bad, the second thing that the British need to realise about the Chinese is that they are much – much – bigger than we are. GDP about six times bigger (depending on how you count it); population 20 times bigger; financial resources and global reach, no comparison. If and when the Chinese consent to offer us a trade deal it will be on their terms. It will be no easier than the talks with the EU or what the Americans will in due course demand (including those chlorinated chickens).