Collaborator is a word to describe people who actively chose to help the enemy during the Second World War. We often think of spies and secret agents. Sometimes they were known as the "Fifth Column."

This term originated in 1936 during the Spanish Civil War. When 4 of his army columns were moving towards Madrid a Nationalist general referred to his supporters in the city as his "fifth column" because they were going to help him bring down the Republican government from within the city. Since then a "Fifth column" has come to mean a group of people who secretly infiltrate another group with the purpose of undermining it. This can also be a in a country, in this case a group enters the country during a time of war with the purpose of working against that country. German agents helped by British agents working for Nazi Germany were active in Great Britain during the Second World War.

The internment of German citizens (known as "aliens") living in Great Britain during the Second World War and just under 2.000 British citizens and Japanese Americans in the United States was justified on the basis that these people would act as a fifth column.

Not only were "aliens" suspected, but those who were members of the British Union of Fascists (the British fascist party). These groups felt that they became "scapegoats" during the so-called "fifth column" scare.