xxvi•INTRODUCTION
unique, in terms of both the remarkable personalities drawn into it and
the part it has played, and continues to perform, in British life, from the
controversy surrounding the Zinoviev Letter to the more recent suicide
of Dr. David Kelly, the Defence Intelligence analyst. Alphabetically,
the list of historic events founded in intelligence runs from the Abdica-
tion Crisis to the Zulu Wars, and all can be found in the pages that fol-
low. Inevitably, because of the traditional reliance on intelligence, and
the pervasive nature of British secrecy, there is almost always another
dimension to major historical episodes, even if only hints of the truth
emerge 30 years later when official papers are released under the terms
of the Public Records Act. Very often it takes many more decades for
the full story to emerge and for the hidden hand of one of the secret
agencies to be revealed.
However, when the details are disclosed—for example, by the ac-
knowledgment in 1974 that the Allied cryptographers of World War II
read much of the most vital Axis strategic communications and thereby
shortened the war by an estimated two years—the public’s perception
of history can be altered radically. Certainly Generals Dwight D. Eisen-
hower and Bernard Montgomery were impressive tacticians, but in nei-
ther of their autobiographies did they refer to the stunning advantage
they enjoyed over their adversaries, namely, the ability to know their
entire order of battle, future intentions, current plans, and the status of
their armored and Luftwaffe support. Thus the source codenamed
ultraproved to be a trump card, and in the decades that followed,
other cryptanalytical successes, includingvenonaand the comprehen-
sive eavesdropping on Warsaw Pact forces in Eastern Europe, enabled
NATO to preserve a balance of deterrence with vastly inferior numbers.
Whilevenonaallowed the counterintelligence authorities to identify
Klaus Fuchs and Donald Maclean as long-term Soviet moles, the moni-
toring of Soviet wireless and cable traffic gave the West a reliable trip
wire that acted as an early-warning system to prevent the possibility of
a surprise attack.
MI5 and SIS achieved worldwide reputations, partly because of writ-
ers such as Ian Fleming, Somerset Maugham, Len Deighton, and John
le Carre ́, but also because of a series of embarrassing espionage cases,
not the least of which was the scandal of the Cambridge Five, which
cast a shadow over the supposed efficiency of the Security Service for
decades. Thus Britain’s best-known security and intelligence agencies,