Using the Enemy – Converting Detained Terrorists into Spies (Part One: The Double-Cross System)

Logan West Counterintelligence, Intelligence

Using the Enemy – Converting Detained Terrorists into Spies (Part One: The Double-Cross System)

July 8, 2022 | | Counterintelligence | Written by Logan West

“Never Put Too Much Trust in Friends. Learn How to Use Enemies.”

–Robert Greene, Second Law of the 48 Laws of Power

American intelligence services in the War on Terrorism have a key potential tool to make use of in order to advance human intelligence gathering efforts: the utilization of captured terrorists as spies. While the traditional intelligence gathering tactic of debriefing detainees after their apprehension is a method that is regularly exercised, the recruitment of detainees as future assets to be handled by case officers to collect new information does not seem to be practiced. Doing so would offer invaluable insight into enemy intentions and strategies. This article will be the first of a three part series to discuss past efforts at such an initiative, what should be learned from their successes and failures, and how a modern effort can benefit U.S. efforts.

The practice of utilizing captured enemy agents is one that has historical precedence in World War II. British intelligence efforts required a successful counterintelligence campaign both to deceive Nazi leadership about the future plans the Allies were formulating for Europe’s liberation and to manipulate Nazi actions to minimize damage against the British homeland. The vehicle for accomplishing these tasks was the Double Cross system. This strategy turned captured Nazi spies into counterespionage assets for the United Kingdom, who were then used to manipulate German intelligence and military planning to the will of the Allies through feeding them false information. Double Cross contributed to the success of the D-Day invasion by the Allies as well as the redirection of Germany’s V1 and V2 rocket targeting efforts through an aggressive counterespionage effort, proving the viability of turning captured German spies against their own nation for the benefit of their captors.

In the case of U.S. efforts against terrorist organizations, the recruitment of detained terrorists would most likely not be for counterespionage efforts like it was for the British intelligence services. However, the recruitment practices by the United Kingdom’s intelligence services have lessons of successes and failures for the current day. The Double Cross initiative began with the successful apprehension of every spy the Germans had dispatched across the English Channel into the British Isles, thanks mostly to poor tradecraft by the Nazi spies. After their apprehension, British intelligence began the process of attempting to recruit them, starting with understanding what motivated them. As Macintyre explains, the agents that Germany had deployed into Britain to spy for the Third Reich were “a mix of motivations, with only a few assessed to be true Nazi ideologues, with the rest being motivated by a variety of factors such as greed, thrill-seeking, and even coercion.” Once detained, these spies were offered a chance to either change allegiances and spy for the British or face execution. Of the original twenty spies Germany deployed, only four were successfully turned, and were largely considered to be failures as effective spies for Britain. But the operation would continue and later mature into an effective tool for the British, allowing them to influence the enemy through counterespionage endeavors both inside Britain and through deployments abroad. These efforts eventually would develop into Operation Fortitude, which served to misdirect German resources towards defending Pas de Calais, which they were led to falsely believe would be the landing point for the Allied invasion force. The strategy was successful in pulling Nazi military forces away front the true invasion target of Normandy, resulting in a successful landing operation for the Allies. One Double Cross agent that had been part of the operation, Agent Garbo, had been awarded the Iron Cross by Germany on the day of the invasion. Another example of successful counterintelligence utilization of flipped German spies was the successful redirection of German V1 and V2 rockets attacks away from London. The Double Cross agents, as a part of the British Operation Crossbow, had falsely reported high casualty rates by rocket attacks in other areas of the UK to Nazi leadership which was so content with the news that they ignored other forms of intelligence that were accurate in favor of the false reports from the Double Cross agents. Examples like these, while more focused on counterespionage efforts than on intelligence gathering, show the validity of such a strategy.

The primary lessons that Double Cross offers to modern day policymakers and intelligence officers is the value of a trusted source’s information to the enemy, recognition and expectation of a high level of failure for turning such assets, and potential reward of success. For the Nazi intelligence services, these spies acted as their only eyes and ears into the British homeland. Because these spies were the Nazis’ only source of information into the United Kingdom, their capture and conversion manipulated the whole of Nazi understanding with limited to no other sources to cross-check intelligence provided. Such a scenario is not likely to be replicated in the modern day when the advance of technology and its ready availability to the public is considered. Any information can now be cross-checked with plethora of sources open to the public. What plays to the favor of a turned asset today, however, is the level of trust they have with the master they supposedly serve.

As previously mentioned, the accurate telemetry readouts from the V1 and V2 rockets depicting missed targets were ignored in favor of the false statements of flipped spies because of Nazi leadership’s desire to trust their human spies more than electronic data. With regards to rate of failure versus success, one can expect a high one. In the case of Double Cross, almost all of the spies that were captured initially were considered failures, either in efforts to turn their allegiances or in effectiveness as double agents. A similarly low rate of turning success can be expected today. When dealing with an enemy that is ideologically motivated and exalts self-sacrifice, the likelihood of choosing martyrdom over conversion is the more probable outcome. However, the relatively high level of failure can be arguably considered one with moderate to little, to even no negative consequence, aside from lost time and effort. When dealing with a captured enemy, failing to convert potential assets will result in them being returned to incarceration or being prosecuted. However, should the target initially play at cooperation only to flee after being released, the result is, once again, lost time and effort, along with the knowledge being potentially passed to the enemy that the intelligence services are attempting to develop spies among captured enemies. The loss of time and effort is not inconsequential, as it results in intelligence personnel not being able to work on other projects or missions. However, the massive potential upside for such an operation succeeding is evident.


The efforts of the Double Cross initiative resulted in manipulating Nazi V1 and V2 strikes which saved thousands of lives and supported the success of the D-Day invasion, leading to the Nazis’ defeat. Today, such successes could lend insight into future terrorist attacks or manipulate and sabotage their plans. Had the U.S. successfully recruited captured Taliban leaders before releasing them in the prisoner exchange for U.S. Army deserter Bowe Berghdehl, American leadership may have gained valuable insight into Taliban strategies and intentions rather than face the intelligence black hole it now has in Afghanistan. Potential success must be balanced against a high likelihood of failure as well as against the possibility of heading off an even worse failure in the future that would come from not even attempting such an initiative. Such is often the case when working in human intelligence.



Macintyre, B. (2012) Double Cross: The True Story of The D-Day Spies. Broadway Books.

Irving, David (1964). The Mare's Nest. London: William Kimber & Co. pp. 251–53, 257–58