Leo Marks; Devised Codes in WWII for British Agents

Leo Marks, a cryptographer who used silk squares printed with rows of numbers to transmit codes to British agents in Europe during World War II, died Jan. 15. He was 80.

Marks worked in the Special Operations Executive, formed by Prime Minister Winston Churchill in 1940 with orders to “set Europe ablaze” by infiltrating agents behind enemy lines to carry out sabotage and set up secret armies.

In his work, Marks was acutely aware that agents were being tortured and killed, and those painful memories were included in a book, “Between Silk and Cyanide,” published in 1999. “If you brief an agent on a Monday, and on Thursday you read that he has had his eyes taken out with a fork, you age rapidly,” he said, recalling the fate of an agent in Yugoslavia. The title derived from Marks’ campaign to introduce codes printed on silk squares that could be destroyed by a far safer method than the unreliable, easy-to-crack poem codes then in common use.

Facing strong opposition within the Special Operations Executive, he did much of his work in secret.

Marks then worked out a system in which rows of unique codes were printed on squares of silk, which were easy to hide and could be destroyed, bit by bit, as each row of numbers was used.

Successes of the Special Operations Executive included the destruction of an atomic weapons plant in Norway, spying on Hitler’s long-range missiles base, and providing the intelligence that led to the sinking of the Bismarck, a German vessel.

An intense character of fierce intelligence, Marks greatly regretted that it took him two years to convince his superiors that the Special Operations Executive’s Dutch secret army had been infiltrated by the Germans. During that time, about 50 agents died.

“I feel guilty for not saving more agents,” he said.

Before the silk squares, the Special Operations Executive had used well-known poems as keys to code.

Marks thought the codes would be safer if they were hidden in original poetry, and 20 of his poems were included in the book.

One of the poems was written to a woman named Ruth, whom he loved deeply, and who died in an air crash in Canada in 1943 before he could tell her.

“The life that I have

Is all that I have

And the life that I have

Is yours

The love that I have

Of the life that I have

Is yours and yours and yours

A sleep I shall have

A rest I shall have

Yet death will be but a pause

For the peace of my years

In the long green grass.”

Among Marks’ agents who died was Violette Szabo, whose story was told in the film “Carve Her Name With Pride.”

In his later years, Marks wrote a successful play, “The Girl Who Couldn’t Quite,” about a girl who had lost the ability to laugh, and a film, “Peeping Tom,” about a photographer obsessed with watching women on the verge of death.

Marks was divorced and had no children.