‘AGD’ - THE SECRET CODE-BREAKER OF
TWO WORLD WARS
by JOHN ROWLEY
Commander Alastair Guthrie
Denniston, CBE, CMG (1890-1961) - known as
‘AGD’ - served his country in almost total secrecy for 30 years spanning both
world wars. He and his family lived in Ashtead from 1937 to 1947.
AGD was born in Scotland
to a doctor’s family. They moved south for health reasons, settling near
Altrincham, Cheshire , where he attended Bowdon College .
After finishing school he attended universities in Bonn
and Paris and then became a language teacher,
eventually working at Osborne College on the Isle of Wight
from 1909. (A keen hockey player, he was also in the Scottish team at the 1908
Olympics in London.)
On the outbreak of World War 1 in 1914, the
Admiralty sought linguists and recruited him and three others from Osborne.
This was the beginning of code-breaking and translation intelligence embodied
in today’s Government Communications Headquarters (GCHQ). It was then known enigmatically as
‘Room 40’, simply a room within the Old
Admiralty Building .
AGD played a crucial role in bringing about
US entry into the war on the
Allied side by translating a decoded German telegram to Germany ’s
Embassy in Mexico revealing
a proposed invasion of US
territory. As all transatlantic cables passed through London , the General Post Office was able to
provide copies for examination.
In 1917, AGD was appointed a Commander in
the Royal Navy Volunteer Reserve. In 1918 he was despatched to the Fleet
flagship taking the German surrender at Scapa Flow and then participated in the
Versailles
peace conference, monitoring communications.
Room 40 became the Government Code &
Cypher School
which continued naval, diplomatic and commercial traffic intelligence in
peacetime. Following a merger with army intelligence, AGD became director of
the GC&CS. Holding the OBE since 1918, he was also given the CBE in
1933.
During the late 1930s he worked with French
and Polish colleagues examining mechanised coding methods developed in Germany . Shortly
before the outbreak of World War 2 he led a delegation to Poland to see a
code-breaking device whose principle would later be developed into the Enigma
machine.
With the growth in intelligence officer
numbers he was involved in moving the GC&CS to Bletchley Park
early in 1939 and its renaming as GCHQ.
AGD had married in 1918 and in 1936 his wife
Dorothy organised a move of the family home from Chelsea to Ashtead. They arrived on 21 May
1937, living on the Berg estate. After working with a local builder, O.W.
Presland, they moved into North End, Greville Park Avenue on 2 January 1938 and
their son Robin started at Downsend
School while his sister
Margaret went to Parsons Mead. Retaining their Surrey home, they moved to a
farmhouse nearer Bletchley
Park in 1939.
Running
GCHQ, AGD recruited steadily at all levels, especially from Oxbridge using
methods evolved by the secret services. Famous figures included the great Alan
Turing. Flow lines for receiving messages from dispersed radio interception
stations through to actionable intelligence were established using huts in the
grounds of Bletchley
Park .
In 1941, AGD underwent bladder surgery and
was eventually recalled to London
where he became director of a reborn Room 40 at an office in Berkeley Street . There code-breaking
continued for many additional languages, Japanese in particular.
On the weekend of 22-23 May 1943, AGD hosted
an American intelligence colleague, Col William Friedman, at his home in
Ashtead. They watched a cricket match in Woodfield Lane and played golf at
Tyrrells Wood. The Dennistons were well integrated into local sporting life.
AGD left the public service in May 1945 and
returned to teaching at Downsend School . The couple sold North End in
September 1947, moving to the New Forest to be
near Margaret. Dorothy died in 1958 and AGD in 1961.
Curiously perhaps, AGD, the first ever
director of GCHQ, died without receiving any obituaries or official attendance
at his funeral. However, on hearing the news, Friedman wrote to Margaret: ‘Your father was a great man, in
whose debt all English-speaking people will remain for a very long time, if not
forever. That so very few of them should know exactly what he did toward
achievement of victory in World Wars 1 and 2 is the sad part of the untold
story of his life and of his great contributions to that victory.’
ARCHAEOLOGY AT ROWHURST - THE STORY
SO FAR
by NIGEL BOND, DIRECTOR OF
EXCAVATIONS
The first excavations at Rowhurst, Leatherhead, took place
in three weeks of May and one week in
October. They form part of the Surrey Archaeological Society’s county-wide
Heritage Lottery Funded community outreach project.
This project aims
to engage members of the public in archaeology and learn more of their local
heritage. We were pleased to have a number of people join SyAS’s experienced
diggers for test-pitting at the weekends, pupils and teachers from West Hill
School for a hand-on
excavation experience, and many people attending our open day in May.
In all, we excavated
ten one-metre square test-pits, the deepest down to 1.2m, and six trenches one
metre wide and up to 8m long. As well as
a large quantity of 19th and 20th century material we were excited to discover
prehistoric and Roman material distributed across much of the site.
Prehistoric pottery
dates to the Late Bronze Age / Early Iron Age (900-600 BC). The Roman pottery
included a large piece of a wine jar (amphora) made in southern Spain around
170-300 AD. This was found at the bottom of what appears to be a hole for a
timber post, our first evidence of early construction activity on the site.
We also found
several pieces of a Medieval pot from 1050-1250 AD. On future digs we will be looking for more
evidence from prehistoric to Roman, Saxon, Medieval and later periods.
Eventually we hope to build a picture of people’s lives at Rowhurst through
time.
The Domesday Book
tells us there is a lost Saxon minster church to be found somewhere in this
part of Leatherhead. It may be awaiting discovery within Rowhurst’s grounds.
WALKING IN LEATHERHEAD
by BILL WHITMAN
In the last few years the birds and
beasts to be seen when walking by the river in Leatherhead have changed.
Gill Whitman’s compilation of photos taken in 2012-13 featured piebald
horses and cows that no longer graze on Leatherhead’s Town Meadow. Egrets and a
cormorant are now commonly seen but were not there when these photos were taken
but unusual diving ducks, a pair of Scaups, were photographed.
The gentle musical background blended well with herons and swans in
flight and ungainly cygnets finding their feet. There were also lovely
photographs of butterflies, flowers, trees and fungi in the short presentation.