368 • MO5
had been the colonel in charge of MO5) came into force, wherever
possible in the form of Orders in Council. The Home Section of the
Secret Service Bureau was given responsibility forcounterespio-
nage, aliens, and the control of civilian traffic overseas. MO5(g)’s
duties were defined as military policy in relation to the civil popula-
tion, including aliens, and ensuring compliance withDefence of the
Realm Act(DORA) regulations insofar as they concerned the MO
Directorate.
Before the war, all aliens living in the United Kingdom had been
registered, with the exception of the East End of London, and lists of
those who were suspected German spies had been drawn up and
passed to the chief constables. Upon the declaration of war, these in-
dividuals were arrested and the German intelligence system in Brit-
ain was totally disrupted.
The war necessitated a major increase in staff. On 1 October 1914
MO5(g) was divided into three subsections: MO5(g)A, responsible
for the investigation of espionage and of persons suspected of espio-
nage; MO5(g)B, responsible for coordination of overall policy of
government departments in relation to aliens and issues relating to
DORA on the Aliens Restrictions Order; and MO5(g)C, responsible
for theRegistry, personnel, administration, and port control. The
section was not housed in the War Office, where it retained only a
single room as a postal department.
An April 1915 War Office reorganization created aDirectorate of
Special Intelligenceunder BrigadierSir George Cockerill, with
MO5 forming part of it. On 11 August 1915, MO5(g) was reorga-
nized, adding a new subsection. MO5(g)A became MO5(g),
MO5(g)B became MO5(f ), and MO5(g)C became MO5(h). The new
subsection was designed MO5(e) and dealt with issues of military
policy in connection with the control of civilian passenger movement
from the United Kingdom and, within that, matters of port intelli-
gence and the issue of military permits. MO5(e) would later super-
vise the creation of Military Permit Offices in London, Paris, Rome,
New York, and Brussels, with MO5(h) handling the administration.
In December 1915, the War Office established a new Military In-
telligence Directorate, which took control over Kell’s group. Soon
after, MO5 was redesignated MI5.