The identity discs were service-issue, in the correct format. The photographs on the identity card and the CCOHQ staff pass were chosen to be consistent with Martin’s claimed appearance. The briefcase that carried the official documents was a standard type used by officers of Martin’s seniority.
The combination of all these items was designed to create the impression of a real person whose life happened to include an important official assignment. No single item was indispensable. The combination was what counted. A German intelligence analyst examining the collection would find, not a carefully prepared prop, but the accumulated detritus of a real man’s pockets — imperfect, uncoordinated, suggesting carelessness rather than design.
One detail that is sometimes mentioned in popular accounts but deserves careful qualification is the sardine comment in Mountbatten’s letter to Admiral of the Fleet Sir Andrew Cunningham. The letter, written in Mountbatten’s voice, referred to Operation Brimstone as the attack on Sardinia (“Sardinia” — “sardines”) as if in an offhand personal way. This was a small embedded confirmation of the deception’s target, designed to reinforce the impression created by the Nye letter. Whether the sardine pun was part of the original letter draft or added later, and whether any German analyst noticed or was amused by it, is not clearly documented.
What is documented is that the collection of documents and personal effects was assembled with considerable care over a period of weeks, with multiple people involved in different aspects of the preparation. The briefcase was attached to Martin’s body by a standard courier’s chain — the kind used to prevent documents from being lost in transit — which was itself a detail consistent with the importance of the documents he was supposed to be carrying.