This article discusses how multiple Internet of Things devices in smart cities pose a potential security nightmare. But who is responsible for security in a smart city? Usually it is the government or local authority, but that is changing, says Ansgar Schlautmann, Associate Director at Arthur D. Little. He explains, “Smart cities involve an ecosystem of suppliers, including operators. A good example of a telco playing a major role is Valencia, where Telefonica is the main contractor. We see telcos are actively looking at running smart cities. We suggested to one of the telcos we supported that it act as a general contractor and find the IT companies and vendors.”