LEO MARKS, who has
died aged 80, was the chief cryptographer of Special Operations Executive
during the Second World War; later he wrote the script for Peeping Tom, the
film which destroyed the career of its director Michael Powell.
Between 1942, when he
joined SOE, and 1946, when he rejected an offer of employment from MI6, Marks
proved himself a code-maker and breaker of rare genius.
While still in his
early twenties he revolutionised the construction and security of SOE's
cyphers. And by his re-invention of the "one-time pad" he eventually
influenced code systems used by secret services the world over.
In the latter stages
of the war he was entrusted with devising encryption systems for, among
others, the SAS and the Free French. Unbeknown to the latter, Marks had
already cracked General de Gaulle's private cypher in a spare moment on the
He began his career as
a cryptographer at the age of eight in his father's antiquarian bookshop in
London, Marks & Co, later the subject of Helen Hanff's memoir 84 Charing
Cross Road (1971).
One morning his father
Benjamin showed Leo a first edition of The Gold Bug by Edgar Allan Poe, which
he had just bought for £6 10s. Knowing that it would interest American
collectors, he intended to price it at £850.
The book's tale of
hidden treasure the whereabouts of which was concealed by a cypher entranced
Leo, and he set about breaking his father's own secret pricing code, a series
of letters pencilled inside the cover of each book.
Within minutes he had
found the key (the 10 letters of Marks Cohen, the two partners in the
business, each corresponded to a number) and gained two ambitions: to become
an expert on codes and, like Poe, to write horror stories.
In January 1942, Marks
was called up and went to Bedford to train as a cryptographer, an opening
secured for him by a godfather in Special Branch.
He was the only one of
his intake not to be sent on to Bletchley Park; instead, having in an evening
cracked a code intended to be spread as a group exercise across a week, he was
labelled a misfit and dispatched to Baker Street, the headquarters of the
recently formed Special Operations Executive.
Marks almost contrived
to fail his interview, taking all day to break a cypher that he had been
expected to decode in only 20 minutes with the help of a key. SOE's head of
codes had forgotten to give him the necessary piece of paper, and in his
memoir Between Silk and Cyanide (1998) Marks drew a vivid and often angry
portrait of an organisation capable of both brilliance and lethal
carelessness. It was also one in which Marks, as a quick-witted Jew, often
felt an outsider.
The title of his book
referred to the new codes Marks had devised and had had printed on silk
squares, and the poison carried by agents - life and death. He had had to come
up with new cyphers because when he inspected SOE's methods for communicating
with its agents in the field he was horrified to discover that the traffic
could be read by the Germans with ease.
The agents were using
well-known poems as the cyphers for encoding their messages, and these could
either be guessed by an enemy armed with reference books, or simply tortured
out of captured operatives.
His initial solution
was to use original poems instead as cyphers. Many of these he wrote himself,
the best known being that which he gave to the agent Violette Szabo, The Life
That I Have. He had actually written it for a girl with whom he was in love,
the news of whose death in an air crash he heard on Christmas Eve 1943.
The poem was
subsequently used in the film made about Violette Szabo, Carve Her Name With
Pride (1958), and generated an enormous response.
Marks took great pains
to get to know the agents he briefed, among them his close friend Forest
Yeo-Thomas - "The White Rabbit" - and Noor Inayat Khan, who suffered
from the handicap for a spy of having been brought up never to lie.
It could be difficult,
as happened to Marks, to brief a man and then hear two days later that the
Gestapo had tortured him horribly. But it was vital for him to understand the
temperament of each agent, as this helped him with the other important area of
his work, deciphering the garbled messages transmitted by agents under stress.
It was vital that any
such "indecipherables" - up to 20 per cent of the daily traffic -
should be read as quickly as possible so that, with the Gestapo on the prowl,
the agent need not risk his life to resend it.
As Marks knew the
coding idiosyncrasies of each agent - an inability to spell a certain word or
a habit of transposing two columns in a cypher - he was often able to decipher
the signals himself, but he also recruited 400 young women from the First Aid
Nursing Yeomanry (Fany) to help him break indecipherables.
these girls Marks did not look for mathematical ability but for an interest in
music and an aptitude for crosswords, believing these were better pointers to
cryptographic talent; he himself was already regularly setting crosswords for
Marks's helpers, based
at Grendon Underwood in Buckinghamshire, proved immensely proficient and
dedicated. One message was deciphered with seconds to spare after 650,000
It was the lack of
indecipherables in the traffic of SOE's Dutch section which first alerted
Marks to the so-called Englandspiel, the most serious disaster to befall SOE.
Marks deduced that
since no signals from Holland were ever corrupted, the Germans must have
penetrated the network and be controlling the transmitters. He was right, but
his suspicions fell on deaf ears - or on those playing a longer game - and up
to 50 Dutch agents went unnecessarily to their deaths.
concentrated on perfecting codes that could not be discovered by the Germans.
His solution was simple and brilliant - to use one-off cyphers, printed on
silk which the agent then cut away and burnt so that he could not remember
keys" not only reduced the incidence of garbling but, being random in
origin, were much harder for the Germans to crack. Silk also had the advantage
of being easily hidden in the lining of clothes, and if they were caught each
agent was given a method of letting SOE know that he was transmitting under
By D-Day, when SOE's
agents tied down thousands of German troops, Marks's silks were being used
from Normandy to Sarawak. They were particularly gratefully received by the
Free French, who routed all their traffic through SOE, allowing Marks to read
politically sensitive material destined for de Gaulle.
By then he had also
refined the one-time pad, first invented by the Germans, in which a code was
made by adding to numbers representing set phrases another pre-agreed series
of numbers. The only copies of these were held by the agent and his masters,
and used just once.
Marks, who needed no
invitation to demonstrate his intelligence, adapted the system to use letters
instead of numbers, an idea already being used independently at Bletchley.
But Marks's drive and
determination ensured that the code became widely disseminated within the
British secret services, and in time it became standard cryptographic
He retained discreet
informal links with the Intelligence Service after the war and devised several
other important new types of code; indeed, so central did his wartime work
remain to modern cypher practice that he was unable to disclose much of it in
his autobiography, the publication of which was delayed by the authorities for
more than a decade after he had completed it.
Leopold Samuel Marks
was born in London on September 24 1920. An only child, he was educated at St
Paul's and then helped out in his father's shop, where customers included
Charlie Chaplin, Aleister Crowley and Sigmund Freud.
After the war, Marks
turned to writing for the stage and screen, and had some success in the West
End with plays such as The Girl Who Couldn't Quite (1947) and The Best Damn
Lie (1957), which made use of a lie detector.
Indeed much of his
literary work, which in truth was largely forgettable, seemed to hark back to
his previous career. Thus the film Cloudburst (1951) was about a vengeful
codebreaker; Sebastian (1967), with John Gielgud, concerned an academic code
expert turned spy.
Quite different from
all these was Peeping Tom (1960). At its most superficial, it is the shocking
story of a man, terrorised as a child by his father, who grows up obsessed
with fear. He gets his kicks by filming young women as he murders them with a
blade concealed within his camera.
At a deeper level, the
film is a meditation on the voyeuristic nature of cinema. Since the man's
crimes are seen by the audience through his lens, they are in effect asked to
identify themselves with his murderous acts.
intelligent script, influenced by his lifelong interest in psychoanalysis,
contains a number of in-jokes, notably that a director in the film is played
by the blind actor Esmond Knight, and that the name Leo Marks gave his
protagonist was Mark Lewis.
recognised as a strange but serious work, at the time the film proved too
disturbing for audiences and critics. It was described as "evil and
pornographic" and the reaction against it ended the illustrious career of
its director, Michael Powell.
Marks went on to work
with the Boulting Brothers, whom he also almost finished with another film
about a homicidal maniac, Twisted Nerve (1968). He never again reached the
heights of Peeping Tom. So provocative is its reputation that it was not
possible to show it on British television until 1997.
The film is the
primary influence on the cinema of the director Martin Scorsese; he
acknowledged his debt in 1988 when he asked Marks to play the voice of Satan
in his similarly controversial The Last Temptation of Christ.
Marks's father died in
1968, but he was not tempted to take over the shop, living instead quietly in
west London. He was good company, enjoyed showing that he knew more than he
said, but kept secrets as well as any man. Though a natural cynic, he was also
In person he was short
and powerful, with a grip of iron and a voice like new velvet. He was an
habitue of the Special Forces Club.
He married, in 1966
(dissolved 2000), the portrait painter Elena Gaussen.
From Obituary Daily Telegraph 28th January 2001