Yesterday Barack Obama, president of the US, met Hu Jintao, president of the People's Republic of China, for a private meeting. The agenda was long, covering the world economy, climate change and non-proliferation of nuclear weapons. The last two are the most important, over the long run. But the first is the most urgent. If we do not achieve a healthy global economic recovery, hope of a co-operative relationship is likely to prove vain. Yet such a recovery is far from ensured. Worse, some of what is now happening – particularly China's decision to depreciate the renminbi along with the dollar – makes healthy recovery less likely.

This, then, was an opportunity for Mr Obama to tell some brutal truths. I hope he did, after careful briefing from his staff, on the following lines.

“Mr President, as I said in Japan, ‘the US does not seek to contain China, nor does a deeper relationship with China mean a weakening of our bilateral alliances. On the contrary, the rise of a strong, prosperous China can be a source of strength for the community of nations'. For the foreseeable future, our two countries will be the leading players on the world stage. We must approach our challenges in a spirit of co-operation and accommodation. But that is, alas, not happening over your exchange rate policies.