Spies like us: The secret life of Ernest Oldham

The security service files held at The National Archives in series KV 2 reveal that many people involved in espionage, like Foreign Office clerk Ernest Oldham, were ordinary folk who entered an extraordinary world by chance - often with tragic consequences. His story, told through phone intercepts, surveillance notes and secret service reports, reveals the human cost of spying in the 1920s and 1930s.

Dr Nick Barratt works in the Advice and Records Knowledge department. Previously he ran was involved in researching and presenting a number of television series. He has published several books, most recently Greater London: The Story of the Suburbs, and he lectures regularly about history and the media.