How many British spies were there during World War 2?

== == Hundreds of them, and not all were British citizens. Many were from occupied countries like Holland, Belgium, France, and Norway. They made their way to freedom in Britain and volunteered to be trained as secret agents, to be sent back to their home country to spy on the Germans and to organize the resistance movement there. Because they spoke their own language perfectly, they were much more able to fit in without being caught by the German security police.