The nerve centre of the German Resistance

Ex-Abwehr HQ in Berlin, which currently houses Germany’s Defence Ministry

The Bendlerblock in Berlin, which housed German military intelligence, the Abwehr, was the nerve centre of the army resistance against Hitler.

In my first book, The Honorable Traitor, I have Admiral Canaris's office on the top floor, but I've since learned it was more likely one of the rooms with a balcony on the extreme left of the image.

In an interview given to Berlin media in the 1970s, a woman said she remembered him coming out onto the terrace to speak to people walking past below.

I have been unable to find out where Hans Oster's office was within the building, but there are several descriptions of how his desk was covered with half a dozen phones.

Hans Oster is possibly the least well-known figure of Der Widerstand, yet one of its most important

This was the A-Net, a supposedly untappable network of telephone and teleprinter lines linking Oster to Abwehr locations across Germany and occupied Europe - and the co-conspirators within them.

In his book To The Bitter End, Der Widerstand member Hans Bernd Gisevius wrote: ""He once described to me in one sentence his own conception of his function within the Resistance movement.

Hans Bernd Gisevius giving evidence at Nuremberg

“He was standing at his desk looking down pensively at the four or five telephones whose secret circuits connected him with the most diverse authorities. 'This is what I am,' he said. 'I facilitate communications for everyone everywhere.'"