UNITED KINGDOM

World War II

The British Services

MI5 and the XX System

A - M

"The Double Cross System was one of the greatest intelligence coups of the Second World War. J.C. Masterman, Chairman of the Double Cross Committee, concluded that 'we [MI5] actively ran and controlled the German espionage system in this country [Britain].' The Double Cross Committee was known as the Twenty Committee because the Roman numerals, XX, formed a double cross.

"Due to a combination of counter-espionage work prior to the war and signals intelligence during it, MI5 was in a position to monitor and pick up German agents as they were 'dropped' into Britain. These agents were then 'turned' and began working for the British authorities. The preferred communication was via wireless telegraphy (W/T), although secret ink, microphotography and, in some cases, direct contact with the enemy was also employed.

"Initially the Double Cross System was used for counter-espionage purposes, but its comprehensive success provided an excellent conduit for strategic deception, culminating in the D-Day deception operation, known as FORTITUDE. This plan led the Germans into believing that the Pas de Calais was the real landing area of the Allied invasion, rather than Normandy. Further successes were achieved in U-boat and V-weapon deception." [From Public Record Office, "New Document Releases: Security Service Records Release 25-26 November," at http://www.pro.gov.uk/releases/nov2002_mi5/intro.htm]

Click for materials on deception operations in preparation for D-Day (Operation Fortitude) and on deception operations generally.

Booth, Nicholas. ZIGZAG: The Incredible Wartime Exploits of Double Agent Eddie Chapman. London: Portrait, 2007. New York: Arcade, 2007.

Clark comment: "ZIGZAG" was Chapman's codename in MI5's Double-Cross operation. His obituary appears at Telegraph (London). "[Obituary:] Eddie Chapman -- Safe-blower Who Became the Wartime Double Agent Zig-Zag and Outfoxed the Germans," 20 Dec. 1997.

A Publishers Weekly reviewer (via Amazon.com) says that.this is a "lively and sympathetic account" of the petty crook turned double agent. However, the author's "transparent cheerleading for Chapman detracts from an otherwise enjoyable biography." Peake, Studies 51.3 (2007), notes that the author "had the cooperation of Chapman's wife and family, and his story is full of details about [Chapman's] origins, his numerous failed business ventures, his female admirers, his Rolls Royce, and his long, but successful, battles to publish his memoirs and make a movie about his double-agent life." [Footnote omitted]

See also, Macintyre, Agent ZIGZAG (2007); and Owen, The Eddie Chapman Story (1954).

Day, Peter, and Andrew Alderson. "Top German's Spy Blunders Helped Britain to Win War." Electronic Telegraph, 23 Apr. 2000. [http://www.telegraph.co.uk]

Documents at the Public Record Office in London show that "Major Nikolaus Ritter realised as early as 1941,... that his spy network in Britain had been compromised but he never passed on his suspicions to his superiors.... Ritter's failure to report his suspicions paved the way for the success of Operation Double Cross."

Evans, Michael. "Double Dealing Aided the Allies." Times (London), 17 Sep. 1999. [http://www.the-times.co.uk]

The minutes of the XX Committee, "which masterminded the wartime double cross agents," were released by the Public Record Office on 16 September 1999. The minutes "reveal more details of the way the Germans were fooled," showing that the "greatest double cross agent of them all,... Juan Pujol Garcia, codenamed Garbo, played the crucial part in deceiving the Germans over Allied plans for the invasion of Normandy."

Harris, Tomas. Summary of the GARBO Case. London: Public Record Office, 2000.

Lacey, Nicola. A Life of H.L.A. Hart: The Nightmare and the Noble Dream. Oxford: Oxford University Press, 2004.

Erskine, Journal of Intelligence History 8.1 (Summer 2008), notes that most of this book covers Hart's "work as a barrister and academic, but part of chapter 5 deals with his wartime work in MI5 (British counter-intelligence)." His main task with MI5's B division (counter-espionage) "was to assimilate and interpret copious, but often very cryptic, ISOS (Sigint) on the Abwehr and Sicherheitsdienst (SD -- the intelligence service of the SS and Nazi Party), plus huge amounts of data from interrogations, the police and other sources." The author "is a law professor, not an intelligence historian, which leads to some detailed errors and omissions."

Lawless, Jill. "WWII British Spies Frustrated by FBI." Associated Press, 4 Sep. 2007. [http://www.ap.com]

Newly declassified files released on 4 September 2007 by the British National Archives "chart the rocky early years of the relationship" between the FBI and the British Security Service (MI5) "and show how cooperation improved over the course of the war."

[Liddell, Guy.]

See Nigel West, ed., The Guy Liddell Diaries -- 1939-1945: MI5's Director of Counter-Espionage in World War II, 2 vols. (London: Routledge, 2005).

See also, Eunan O'Halpin, "The Liddell Diaries and British Intelligence History," Intelligence and National Security 20, no. 4 (Dec. 2005): 670-686.

Macintyre, Ben. Agent ZIGZAG: The True Wartime Story of Eddie Chapman -- Lover, Betrayer, Hero, Spy. London: Bloomsbury, 2007. New York: Harmony, 2007. New York: Crown, 2008. [pb]

Peake, Studies 51.3 (2007), finds that while he used "primary sources on Chapman's wartime exploits," the author "has little to say about Chapman's pre-and-postwar life." See also, Booth, ZIGZAG (2007); and Owen, The Eddie Chapman Story (1954).

Masterman, John Cecil. The Double-Cross System in the War of 1939-1945. New Haven & London: Yale University Press, 1972. New York: Avon Books, 1972. [pb] New York: Ballantine, 1982. [pb]

Clark comment: Masterman was head of BI(a), the counterespionage arm of MI5, during World War II, and chaired the Double-Cross (XX) Committee that managed the German agents captured and turned beginning in 1940.

Pforzheimer notes that the author "wrote this text as an official classified history"; as released, there has been sanitization. The book remains a "veritable classic treatise" on counterintelligence and deception. The lack of direct references to the Ultra material, which was used to check on the success of these operations, is a major void in the Masterman's presentation.

According to Constantinides, The Double-Cross System is "one of the great works of intelligence literature, an outstanding one in the area of deception, and perhaps the greatest work yet written on double agents." Sexton notes that this "slender volume ought to be essential reading for those seriously interested in intelligence and deception."

In a excellent article that is more than a book review, A.V. Knobelspiesse, "Masterman Revisited," Studies in Intelligence 18, no. 1 (Spring 1974): 25-40, proclaims that "Masterman's book ... merits the appellation 'seminal.'" The work presents "lean, impersonal, underplayed facts," and "combines brevity and conciseness with donnish elegance and challenge.... The codification of [counterintelligence] operational principles which accompanies Masterman's double agent case facts makes this the only book of its kind in public print.... The underlying thrust of the methodological theory and wisdom set out in this book ... apply to any time and to any adversary."

For the debates surrounding Masterman's release of his work and some of the follow-on controversies, see John C. Campbell, "A Retrospective on John Masterman's The Double-Cross System," International Journal of Intelligence and Counterintelligence 18, no. 2 (Summer 2005): 320-353.

McMahon, Paul. "Covert Operations and Official Collaboration: British Intelligence's Dual Approach to Ireland during World War II." Intelligence and National Security 18, no. 1 (Spring 2003): 41-64.

"In the early stages of the war, preoccupied by the threats posed by its neutral neighbour, and possessing little faith in the willingness or ability of the Irish authorities to protect its security, Britain had initially responded by engaging in a series of clandestine intelligence missions in Ireland. Simultaneously, British security organizations began to develop an unprecedented level of cooperation with their Irish counterparts. These two very different approaches were conducted in parallel for most of the conflict, with a surprising absence of friction, but it was eventually realized that all Britain's security needs could be satisfied by collaboration with the Irish authorities."

Miller, Joan. One Girl's War: Personal Exploits in MI5's Most Secret Station. Dublin: Brandon, 1986.

Steiner, I&NS 3.2, calls this "a delightful and entertaining account of the war-time exploits" of a young woman "who entered the secret world of intelligence and became personal assistant to Maxwell Knight,... Chief of MI5's B5 (b) section."

Miller, Russell. Codename TRICYCLE: The True Story of the Second World War's Most Extraordinary Double Agent. London: Secker & Warburg, 2004.

Peake, Studies 49.1 (2005), finds that the author "adds new details to the TRICYCLE story.... He provides many interesting new facts about the Double Cross System and TRICYCLE's handing by MI5, although analysis of their significance in some cases is open to challenge.... [A]lthough Popov was unquestionably a valuable double agent for four years, nothing in the book or his file supports the author's contention that TRICYCLE was the 'most extraordinary double agent' in the Second World War.... [T]he careless errors and many undocumented comments place the book in the easy-to-read-but-of-limited-scholarly-value category."

Montagu, Ewen E.S. Beyond Top Secret Ultra. New York: Coward, McCann & Geoghegan, 1978. London: P. Davies, 1977.

Pforzheimer notes that Montagu was the Naval Intelligence member of the XX Committee headed by Masterman. In particular, Montagu handled the Ultra and Abwehr traffic pertaining to naval deception and intelligence activities within the Committee. He was also the case officer for Operation Mincemeat (described in his The Man Who Never Was). "These memoirs are highly authoritative, as well as a charming and well-written contribution to the literature of intelligence."

To Constantinides, the book is an "outstanding memoir of intelligence" in which there are "many items and anecdotes to delight or to enlighten." However, he finds the chapter on Mincemeat "disappointing in that it contributes nothing new."

Murphy, Christopher J. Security and Special Operations: SOE and MI5 during the Second World War. Basingstoke: Palgrave Macmillan, 2006. New York: St. Martins, 2006.

Thurlow, I&NS 23.2 (Apr. 2008), says this is "a clear and well written study of the security issues investigated by MI5" with regard to SOE's activities during World War II. It "is solidly based on the surviving evidence, and sensible and judicious conclusions have been made about subjects which are still highly controversial.... It fills a much needed gap in its authoritative discussion of the problems and weaknesses of security" in SOE.

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