Yvonne Gomez speaks with Professor David Stupples, Director of Electronic Warfare Research at City, University of London about spy technologies and surveillance systems, and how they've been used for intelligence gathering over at least 200 years.

<p>Yvonne Gomez speaks with Professor David Stupples, Director of Electronic Warfare Research at City, University of London about spy technologies and surveillance systems, and how they've been used for intelligence gathering over at least 200 years.</p>

Exploring the stories behind the headlines

<p>Exploring the stories behind the headlines</p>