American Cryptology during the Cold War - The Black Vault

liaison office had maintained an office in London, and Manson had to cover two locations,
in Eastcote and London. (This situation continues to this day, with NSA holding offices in
both London and Cheltenham.) USLO never controlled the TICOM group, which also
found quarters at Eastcote. 21
The British, meanwhile, had a more difficult problem. While the U.S. dealt with only
one COMINT organization, GCHQ, the British had two - the Army at Arlington Hall
Station and the Navy at Nebraska Avenue. Not wishing to choose, the British
diplomatically located their liaison officer in the State Department building in downtown
Washington. (They did, however, maintain a technical staffat Arlington Hall.) Their first
liaison officer was Colonel Patrick Marr-Johnson, who had signed the BRUSA Agreement
for the British side. When he retired in 1949, he was succeeded by Tiltman, who was
already well known to the Americans and had served for a time as Travis's deputy at
GC&CS. This began a practice, continued to this day, ofassigning very senior cryptologic
officials to the respective liaison offices, and the USLO eventually became SUSLO - Senior
U.S. Liaison Officer. 22
And where were the British Dominions in all this? They were mentioned in the
BRUSA Agreement, and it was agreed that they would not be termed Third Parties, but
they were not direct and immediate partners in 1946. Arrangements that Great Britain
might make with them would be communicated to STANCIB. STANCIB, in turn, would
make no arrangement with a Dominion without coordination with LSIB. Thus the nowfamous
UKUSA Agreement was not that at all~ at least to begin with. It was a BRUSA
Agreement. How it became the UKUSA Agreement was a development that spanned
another eight years.
Of the three dominions with which the Americans eventually associated, the
relationship with Canada began first. Canadian-American SIGINT cooperation appears to
have begun in 1940, in the form of service-to-service collaboration between the respective
armies and navies. These decentralized arrangements were eventually overtaken by a
centralized relationship centering on the Examination Unit of the National Research
Council, established in 1941 as one of those clever cover terms denoting a Canadian SIGINT
organization. Its purpose was to decode traffic to and from the Vichy delegation in Ottawa.
I
This unit's control was gradually broadened until it was the dominant force in Canadian
cryptology. (It was the linear predecessor of the postwar organization Communications
Branch, National Research Council [CBNRC] and its successor, Communications Security
Establishment [CSE].) By 1943 it had its own submarine tracking room and was receiving
plots from the British based on ENIGMA decrypts. When the British began cooperating
with the U.S. in 1941, they requested that the U.S. bring the Examination Unit into the
scope ofthe cooperation. But the Americans were leery. They knew that the Examination
Unit had been established by Herbert O. Yardley, the renegade American cryptologist who
had published cryptologic secrets in 1931 in The American Black Chamber. The Signal
Intelligence Service, which had been victimized by Yardley's revelations, informed the
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