On a high street in suburban London, a curious message appeared recently. Written on a stand-up whiteboard in traditional Chinese, it read: ‘Thank you to Chris Patten, who fought for British residency for Hong Kongers. 4 July – please vote Conservative’.

In the last few years, the leafy commuter town of Sutton, to the south of London, has seen thousands of new arrivals from Hong Kong since the government opened up a route to citizenship for those with British Nationals (Overseas) passports.