After last October's state visit to the UK by President Xi Jinping, the respected China watcher Kerry Brown wrote on The Interpreter that the structure of Sino-British relations for the past several decades was 'of a persistent veering between concord and discord', a pattern set in the '80s by tensions over the future of Hong Kong:

The question with the current Xi Jinping visit to London is whether we are just seeing a high point in the usual cyclical pattern, and that we should expect the usual dip fairly soon.

That question may now have been answered, given Beijing's cool reaction to the Queen's criticisms of Chinese diplomats, caught on camera (see above).

The end of Brown's piece is also worth quoting in the circumstances:

The UK has pushed the boat out for this visit. It has a lot to lose, with its allies in particular, if this does not work. If a steady, strong flow of good economic collaboration starts, and Europeans, Americans and Australians see knock-on benefits, then this story has a good ending. But if another dip happens in the next few months or year, it will be proof that the UK and China have profound problems that they have still not managed to overcome.