A Fraudster’s Lisbon Trip and the End of the SNOW Case
By Constance Bell ·
The Security Service used a convicted trickster to monitor a Canadian engineer, a move that ended in a German interrogation and the total collapse of a high-stakes double agent operation.
A fraudster’s Lisbon trip and the end of the SNOW case
An engineer’s life was dismantled and a high-stakes intelligence network was liquidated because the Security Service decided to gamble on a man with a criminal record. The cost was the total compromise of a double agent and the abandonment of a critical intelligence stream during the height of the war.
The record, a catalogue description from the National Archives, provides the skeleton of a disaster. It details how a man named CELERY, a professional confidence trickster with a history of illegal living, was used to shadow a primary intelligence asset, resulting in a trip to Germany and the sudden, unexplained termination of a major operation.
The South London Connection
The line between the legitimate world of intelligence and the underworld of the professional con was drawn in a South London pub in March 1940. It was here that SNOW, a Welsh-born, naturalized Canadian electrical engineer who had been reporting information to British Naval Intelligence since 1936, met CELERY.
According to the record, CELERY was no stranger to the fringes of respectability. Having served in Air Intelligence during the First World War, he had spent the following decade building a reputation for deceit, accumulating a string of convictions for confidence trickery and living precariously on his wits. The meeting in the pub was not a coincidence of circumstance but a moment of predatory cultivation. SNOW, an operative with deep ties to the Secret Intelligence Service, began to cultivate CELERY, hinting strongly at the existence of an intelligence role.
If the shape of this file is what it appears to be, CELERY’s initial reaction was not one of a recruit, but of a man looking for a way to scrub his record. In April 1940, CELERY attempted to report his suspicions of SNOW to his former employers in Air Intelligence. He claimed he wished to restore his good name and secure worthwhile wartime work. The desk's reading is that this was CELERY’s first major play—a calculated maneuver to turn his proximity to a high-level operative into institutional leverage. He was not reporting a threat; he was auditioning for a role.
The Notional Sub-Agent
By October 1940, the Security Service—the British agency responsible for domestic intelligence—had accepted the pitch. They recruited CELERY as a roving collector of intelligence, a role designed to be provided to the Germans "notionally" by the SNOW network. The use of the word "notional" is the most significant clue in the file. It suggests that the relationship between CELERY and the primary agent was a fiction, a layer of shadow meant to provide the Security Service with a degree of separation.
CELERY was not just a collector; he was a monitor. His task was to report on SNOW himself. This was a dangerous architecture, placing a man whose entire professional existence was based on deception in a position to observe a man whose professional existence was based on the careful management of deception. The Security Service was using a known fraudster to watch a professional double agent, creating a feedback loop of instability.
This arrangement culminated in February 1941 in Lisbon, the capital of Portugal and a notorious neutral ground for wartime espionage. CELERY traveled to Lisbon with SNOW to meet RITTER, the case officer responsible for managing the SNOW network. The meeting was intended to formalize CELERY’s role within the German intelligence web, but it instead triggered a catastrophic failure. SNOW later claimed that during this meeting, RITTER accused him of working for the British. In the ensuing confrontation, SNOW confessed his role and attempted to warn CELERY, but CELERY denied any knowledge of the truth.
The German Interrogation
The failure in Lisbon led directly to CELERY’s transit to Germany, where he was taken as a guest of the Abwehr, the German military-intelligence service. The Abwehr held him for close questioning. While CELERY later claimed he survived his time in Germany without making any "damaging admissions," the fact that he was detained by the Reich’s intelligence apparatus is a testament to how quickly the Security Service's experiment unraveled.
CELERY eventually returned to the United Kingdom through Portugal, a journey that marked the end of the operation. Following his return, both SNOW and CELERY were subjected to extensive interrogation, both together and separately, regarding the events in Lisbon and Germany. The record is blunt: "No definitive conclusion was reached," yet the consequence was immediate. The SNOW case was terminated.
There is a profound silence in the archive where the results of those interrogations should be. We are left with a summary that avoids the truth of what was learned in those rooms. The pattern suggests that the Security Service was not merely unable to reach a conclusion, but was unable to admit that their attempt to use a criminal as a deniable monitor had resulted in the total exposure of their asset.
A Burnt Network
The desk's reading is that the "termination" of the SNOW case was a bureaucratic euphemism for a total operational compromise. When an intelligence agency terminates a case following a high-level interrogation by the enemy, it is not because they have finished their work; it is because the work has been burned. The connection between the engineer and the trickster, which the Security Service thought they could manipulate, became the very bridge the Abwehr used to cross into the heart of the operation.
If a full release of these files were possible, it would likely show that the withheld pages contain the actual interrogation transcripts from Germany—transcripts that would have exposed exactly how much the Abwehr learned from CELERY’s presence. The gap in the record is not an accident of history; it is a shield. It protects the Security Service from the reality that they deliberately placed a man of no character into a position of high trust, knowing that his primary instinct would always be self-preservation over national interest.
The SNOW case did not end because of a lack of evidence. It ended because the Security Service attempted to play a game of shadows with a man who lived in the dark, and in doing so, they handed the Germans the keys to the network. The cost was the loss of a trained, naturalized Canadian engineer and the silencing of a vital intelligence line, all to satisfy a desire for a deniable asset that was never truly deniable.