Writing historical fiction means doing a lot of research - and I mean a lot! Usually this is to ensure that the story fits into the timeline of history correctly or to check minor but important details that if I get wrong can grate with a reader.

Sometimes the research b rings the plot to a screeching halt. Sometimes though, the research offers up an opportunity to add to the pot and the entire direction of the novel.

Such was the case with research I did for my forthcoming book, Lisbon '41.

As the name suggests, the novel is set in wartime Lisbon, a fascinating place and time. The dictator of Portugal, Antonio Salazar, a former university Economics professor, kept his country neutral in the face of incredible pressure from both the Axis and Allied sides to favour one or the other. Lisbon became a hotbed of espionage and scheming. Ian Fleming, for example, was a key player in British Intelligence and had the idea for the first Bond novel by his visits to casinos in Estoril during wartime.

When I was plotting the book I had one of those 'what if' moments that often inspire writers of fiction. Mine was What if a meeting occured between parties who absolutely should not have met in wartime? And what if a recording of that meeting existed?

That lead to me hitting the research trail. Just what was possible in 1940? Did the technology exist to enable this to happen?'

Obviously I knew about things like wire recorders and dictaphones. The existance of the latter was a central plot device for Agatha Christie's classic The Murder of Roger Ackroyd written in the 1920s. But that device was in the room and was quite large and bulky. My question was whether a covert device could have existed then.

Sometimes research makes the job of a historical fiction writer harder. Occasionally - very, very occasionally - it gives the author a huge present that's like Christmas and birthday rolled into one.

This is what I found:

During WW2 the Allies noticed that certain German officials were making radio broadcasts from multiple time zones almost simultaneously.Analysts...believed that the broadcasts had to be transcriptions, but their audio quality was indistinguishable from that of a live broadcast and their duration was far longer than was possible even with 16 rpm transcription discs. In the final stages of the war in Europe, the Allies' capture of a number of German Magnetophon recorders from Radio Luxembourg aroused great interest. These recorders incorporated all the key technological features of modern analog magnetic recording and were the basis for future developments in the field. (Wikipedia)

Yes, the Germans had secretly invented magnetic tape recording in the late 1930s and had developed it during the war! This was exotic technology and a huge leap forward in audio quality. The Americans in particular took this technology on and it rapidly became the basis of audio recording in radio, television and film. By 1952 wire recorders were dead. By the 1960s domestic reel-to-reel tapes had reached the domestic market. Although LPs and Singles were still on disk, the master tapes that created them in the studio were on magnetic tape.

And, of course, spies and bugging from the late 1940s onwards relied on magnetic tape and tape recorders.

I hadn't got a plot hole. I had found my plot opportunity.