Black jacket buttoned-up and black wheeled-suitcase in tow, Michelle Teran could have been just anybody, wandering around the Central Station area on this grey Cardiff afternoon. Little did passers-by know, concealed in her clothing was a video scanner and a mic, picking up tit-bits of signals being broadcast by surveillance cameras and being screened on the back of the case she tugged along behind her.

A policewoman, oblivious to the technology hidden away, asks Michelle whether she is looking for the station. "No," she replies blankly whilst her audience c