Wen Jiabao occupies a unique place in the firmament of elite Chinese politics. The consummate insider, he is also one of the very few in the last few years who have made ostensibly liberal comments about the need for deeper and quicker political reform in China. More importantly for the EU, he has been one of its main supporters, and has done his best to nurture and support the relationship.
Wen the reformer
Wen's visit is almost certainly his last to the UK. But that doesn't mean after his expected retirement next year that he will disappear. In Chinese politics, there are rarely second acts, largely because people maintain influence in the dense undergrowth of connections and informal links that sustain the whole vast edifice.
Wen's most probable legacy, through his protégés (in particular, his likely replacement Li Keqiang, who visited the UK earlier this year) will be on the more reformist wing of the party. It is for this reason that, as a politician, he, and his cause, need to be supported.
China still lavishes surprising levels of attention on the UK. It long overtook the size of the UK economy. And the handback of Hong Kong is now but a distant memory. But elite leaders still come here regularly, as do ministers from the UK to China. And the UK still attracts more Chinese outward investment than anywhere else in Europe.
Deepening financial links
The UK can't rest on its laurels though. Chinese money is becoming a bigger issue and there is a lot of competition to get it. Africa, the Middle East, Latin America, and North America are now all lining up to convince China of the merits of placing more of its outward investment in their countries. The problem for the UK has been we don't manufacture many of the things the Chinese want (and at the moment that means cars, which is the heart of the healthy German trade figures with the PRC), and the greatest strengths of our economy are in areas like financial services or creative industries where China is not quite ready to deepen the links.
There are clear reasons why a Chinese leader would want to visit the UK when they are in Europe. The first is the huge number of students from the mainland that study here. The second is the fact that diplomatically, as a fellow permanent member of the UN P5 Security Council, there are always issues to discuss. The third is the dense business, academic and personal links that exist outside the level of government between the two countries.
But the real challenge will be how often these high level visits happen after the leadership change in 2012. The worst outcome for the UK would be to look back at this era as the final one when there were frequent visits of this nature.
The UK government is going to have a tough line to tread between continuing to be 'frank' and explicit on human rights, something Mr Cameron evidently feels a deep personal interest in (he has been far more open both in China, and in the UK, about this issue than former Prime Ministers Blair or Brown were), and cultivating deeper and bigger business links. Getting the balance right has never been tougher, especially in view of the major clampdown in Beijing in the last few months on rights lawyers and others. And on this issue, Wen has been by way and afar the easiest elite PRC leader to engage with, which means that it is likely the UK, and the EU, will miss him when he is gone.