Sharing a pint of ale and fish and chips at an English country pub is the image often used to mark the start of President Xi Jinping and former UK prime minister David Cameron's "Golden Era" in China-UK relations.

But another picture may be just as telling. In September 2015, one month before Xi's state visit to Britain, then-chancellor George Osborne was photographed aboard a 350-kph bullet train in Chengdu, Sichuan province, where he was wooing Chinese investment in planned high-speed rail lines in the United Kingdom.

The UK, which has a hefty current account deficit and expensive infrastructure plans, is eager for Chinese money.