The stakes are simply too high for diplomats to risk a confrontation with China over its human rights record.
The British government is going to be very pleased with itself after today. Chinese premier Wen Jiabao is wrapping up his visit to the UK, signing off trade deals worth over £1 billion. British businesses are being given greater access to China's fast-growing regional cities, whose GDP has more than doubled in the last three years alone. As if that wasn't enough, Wen is even going to return safe in the knowledge that 800 breeding pigs will be following him. The handshake photo call on the steps of No 10 will be thoroughly appropriate: Britain and China are doing business.
It will disgust the group of human rights protesters gathering outside Downing Street as I write. China's treatment of Tibetan demonstrators is well-documented, but the mass injustices don't get as much attention here as the fate of individual dissidents whose stand against the Chinese elite highlights what the west is really up against. Take Liu Xiaobo, the winner of the Nobel Peace Prize. He remains incarcerated in China: but in the last two weeks, artist Ai Weiwei and human rights activist Hu Jia have been released after periods behind bars. This is not a sign of progress.
"The world's most populous country remains what it has been since 1949," the European parliament's vice-president for human rights and democracy, Edward McMillan-Scott writes, "ruled by a brutal, paranoid and corrupt elite parading itself as a political party". These are the people who Britain is doing business with. Why? Because of the trade imperative, of course. Yes, human rights issues will be raised. But ministers will not push their demands far enough to make a real difference. That's the key test, campaigners say. Anything less is just political hot air.
It was always supposed to be this way, for this is the foreign policy the Conservative party had planned for itself in opposition. David Cameron and foreign secretary William Hague had no grand idealised vision of Britain in the world before they came to power. There was no messianic vision of exporting democracy. Britain would do the right thing and stand up for itself, but never commit Tony Blair's mistakes of inflating his own, and his country's, sense of purpose. Instead the focus would be on promoting trade - just as well, given the cuts to the Foreign Office's budget.
Cameron's first year saw him court the big two emerging economies of the east, China and India, as a priority. Last November's visit to China secured major investment, including one Rolls-Royce deal worth $1.2 billion. The India trip was partly successful because Cameron spoke out against Pakistan, prompting a major diplomatic spat with Islamabad. Both were judged big successes. It felt as if there were no lengths to which Cameron would not go to accelerate the growth of Britain's trade with these countries.
But then came the Arab Spring and, as if from nowhere, a sudden swerve in Britain's foreign policy appeared. The decision to support an intervention in the skies over Libya was a striking shift for a government which had been so distant from the Iraq invasion. British lives were to be risked, once again, to protect civilians facing Muammar Gaddafi's wrath. Here, it seemed, human rights did trump other interests.
Wen, Cameron and their respective staff are meeting in London even as RAF jets continue to patrol, and occasionally conduct air strikes, against Gaddafi's forces. In one case, Britain opted to abandon its oil deals with Tripoli and push for change. Putting pressure on China, even if it falls far short of military action, is unthinkable. This visit serves as a reminder that Cameron and Hague's foreign policy has not suddenly jolted from one direction to another: Britain's primary purpose in the world is still to make money, not war. The Libya conflict shows that, where the balance is right, principles will be put before profit. That is obviously not the case in China - not if the coalition is to meet its target of securing $100 billion of bilateral trade by 2015, at least.