How much of a concern are China’s overseas police stations?

A man sits behind a desk in an estate agent’s office on a busy street in Hendon, a north-western suburb of London. He seems irritated by the arrival of yet another journalist wondering whether this small, plain space—typical of high-street property firms—may have links to the Chinese police. It does not, he insists. He says the first he heard of allegations that it might was late last year, when a human-rights group based in Spain claimed that local police in China had set up dozens of “service stations” abroad, including in America, Britain, Canada and France. The address in Hendon was listed. So was that of a food-delivery business in south London and a restaurant in Glasgow.