With Brexit, spirit of openness may never be the same again

One of my abiding memories of President Xi Jinping's state visit to the United Kingdom in October 2015 was in Manchester.

I was standing in Albert Square among thousands of Chinese students as Xi and former UK prime minister David Cameron had lunch in the city's magnificent Victorian town hall.

I couldn't help but think that I was in the best-connected country in the world. Not only was the UK building a new "golden era" of relations with China but it was also a close ally of the United States, a permanent member of the UN Security Council, an influential player in the Commonwealth and, for many countries, the best route into the European Union.