Oliver Strachey

While at the Foreign Office, he engaged in work on the East Indian Railway and historical research.

He co-authored with his wife Ray a work on Keigwin's Rebellion (1683–84), an episode in the history of Bombay; it was published in 1916.

He headed the ISOS section deciphering various messages on the Abwehr network involved with turned German agents (part of the Double Cross system), with the first decrypt issued on 14 April 1940.

Initially codenamed Pear, the decrypts became known as ISOS, standing for Illicit Services (Oliver Strachey).

This ambiguously named, top secret cypher department was the Canadian equivalent of Bletchley Park.

Strachey brought with him from England, keys to high-level French Vichy and Japanese diplomatic codes, which initiated close cooperation with Washington and London.