Darwin Chen, chairman of Habitat for Humanity China, recently decided to take a closer look at the junk mail arriving at his Hong Kong-based foundation. His investigation, he says, confirmed his long-held concern that “there are unfortunately a lot of bogus and fraudulent charities in Hong Kong”.

Among his findings were four leaflets that carried the same address but sought donations for different charities. The address led Chen to an illegal hut on the roof of a four-storey tenement building.