WikiLeaks 2010 it is not, but the hack of the EU diplomatic service’s internal cables stretching back three years reveals much about the issues that preoccupy the European commission’s foreign policy apparatus, notably the rise of China.

Throughout the cables – more than 1,000 have been leaked to the New York Times – the EU conducts itself as a formidable, functioning foreign policy state with a unified interest. At one point the European commission president, Jean-Claude Juncker, tells the Chinese “the EU expected to be treated as undivided and undividable”.

It is evident that, come Brexit, the UK diplomatic service will be shorn of much its bureaucratic support, if not its eyes and ears. The cables, for instance, include a lengthy memo from the UK asking the EU to tour capitals in Africa to address alleged breaches of sanctions policy towards North Korea. In future, the UK will have to conduct such operations on its own.

The leaks above all reveal the extent to which the EU and China alike are preoccupied with the tweets and disruptive instincts of Donald Trump; they even joke that they share a common enemy in the erratic US president.

In perhaps the most colourful cables, describing an EU-China summit in Beijing in July this year, even Vladimir Putin is cited by Xi Jinping as being equally perplexed by Trump. “While Trump admired Putin, Putin saw Trump as an outlier,” the Chinese premier is quoted as saying.

The EU’s account of the dinner also sympathetically records Xi’s claim that “the US was behaving as if it was fighting in a no-rules freestyle boxing match”. The US wanted to jump out of the global village and tear up the rules of the postwar clubs China had fought so hard to join.

The Chinese premier adds: “The US had thrown all rules out of the window and unilaterally imposed labels on others without providing them with the possibility to defend themselves. Caving in would only encourage the bully.”

And the Chinese leadership is recorded as “wanting to make common cause with the EU in defending the basic elements of the rules-based international trading system against the instability caused by the US’s current actions, but is careful not to single out President Trump for personal criticism”.

The European council president, Donald Tusk, says in reply that China and the EU share an interest in defending a rules-based order but also points to the many trade restrictions imposed by China.

Other cables show the EU’s concern with Trump, including over his optimistic assessment of a breakthrough with North Korea. The EU notes the large cultural gaps that have yet to be bridged between Pyongyang and the west.

An aside in another cable suggests that the Trump-Putin meeting in Helsinki in July this year was “successful (at least for Putin)”. The cables also describe the allegation that Russian agents interfered in the American presidential elections, something that will not please the US president.

Trump is also described as “the greatest force driving Democratic enthusiasm to vote in November”.

A 7 March cable summarised the difficulties in relations between the US and the EU that had developed during the Trump administration. A senior European official in Washington spoke of “messaging efforts” to deal “with the negative attitude to the EU in the beginning, which had created a lot of insecurity”.

The EU’s determination to protect the Iran nuclear deal from the US also features, including an attempt to persuade a wary China to take a leading role in fighting US sanctions. The papers also confirm that the EU regards Iran as possibly on a virtuous trajectory. “Iranian society, in spite of the resilience of a minority of religious hardliners (roughly 10% or so), was largely pro-western and even more so pro-European. This was true particularly of the younger generations, which was promising.”

Trump’s aides, on the other hand, will seize on a remark in one paper written in 2015 stating: “Even in a best-case scenario, according to the deal Iran would presumably become a nuclear threshold state in 15 years.”

The EU will only be relieved that no cable truly lays bare EU diplomats’ widely held view that Trump is on an wrecking mission to break up the EU, either as a competitor to the US or as a symbol of the anti-patriotic multilateralism he detests.

Instead the cables reveal a EU bureaucracy as worried by the rise of China, its rival influence in Africa and the possible role China is playing in undermining sanctions against North Korea. The threat posed by China to human rights worldwide and to EU influence in Africa is admirably recounted.

In a lengthy paper on China in Africa, the EU warns: “Xi’s assertive foreign policy has an impact on Africa. China is more self-assured, with more party control over the economy and society at large, more mercantilist, providing its own authoritarian governance and state-centred development model as an alternative model for developing countries (China is openly critical of democracy as an obsolete model).

“China is generally pushing vocabulary and concepts such as ‘win win’ and ‘community of shared future for mankind’, now inserted into its constitution, in its international relations. This trend – which African countries generally seem less likely to challenge – can influence governance globally, including in Africa.”

The paper adds: “China is vocally proclaiming that its cooperation – in contrast to the ‘western approach’ – has ‘no political strings attached’ and is supposedly based on its ‘non-interference’ principle.”

A separate paper predicts technology will not open up China, saying: “The fact is that deleting accounts or information that is ‘harmful about current politics’ when Chinese citizens are increasingly consuming news and information online is yet another way of preventing interest in and debate about politics on China’s current leadership. What is the preferred mode of communication about political issues? If the Central Party School (or for that matter the content of much of what passes for discussion of politics in Chinese media) is accurate, one could describe it as adulation.”

Russia’s intentions towards Ukraine also feature repeatedly, including unconfirmed Ukrainian claims that Crimea, annexed by Russia four years ago, had been turned into a hot zone “where nuclear warheads might already have been deployed”. Prophetic concerns this summer about Russia’s future activities in the Sea of Azov also feature. Last month Moscow seized three Ukrainian naval ships and their crews. Overall the cables reveal an EU worried by Putin but with few new plans to counter his aggression.

But in the end, it may be the fact of the hack, and what it reveals about modern cyber-security, as much as its diplomatic content for which this episode is likely to be remembered.