Bletchley Park - British Intelligence - World War II
The Achievements of Bletchley Park
Introduction.
Following the most enjoyable weekend with the Leica
Fellowship in Hinckley we decided to take a detour on our way home to revisit
Bletchley Park, which we haven’t been to for about 15 years.
This unique and fascinating museum tells the story of
British intelligence gathering during World War II and is full of literally
incredible stories of intellectual and organisational achievements that made a
significant contribution to the Allies beating Nazi Germany. It also set the foundations for modern
intelligence operations and was the birthplace of electronic, programmable
computers.
This is an incredibly complex story of human endurance,
mathematical and crypto-analytical brilliance and organisational development
that created a large, complex operation that only came into the public domain
as the rules imposed by the Official Secrets Act were relaxed with the passage
of time. Many employees went to their graves holding their secrets.
This story has been the subject of books and films some of
which are more historically correct than others. This is a fuller account than the article I
put onto the website but I am still only skimming the surface of what was
achieved.
If you can, please visit the museum and look at the website:
https://www.bletchleypark.org.uk/
I list a couple of books at the end that will give you a
good feel for how the Park was established and how sophisticated its operations
became.
What Was The Scope Of
Bletchley Park?
In the late 1930s the government moved its Government Code
& Cypher School (GC&CS) away from the risks of being bombed in central
London to this country mansion in Buckinghamshire.
The first photograph shows you the original hall.
Bletchley Park (BP) is most well-known for the story of the
breaking of the German Enigma military encyphering system and the tragic story
of Alan Turing
Turing was a mathematical genius who was key in breaking the
Enigma through his development of the electro-mechanical Bombe machines that
the Poles had first developed. He and his team worked tirelessly to crack the
incredibly complex Enigma codes used by the German military. The vast numbers of combinations of settings
meant there was no chance of just breaking the encyphering settings and daily
codes by hand, luck or accident; there
were 159 million, million, million possibilities. Turing developed the bombe machines to help
them look for ways into the keys and encyphering settings that could not have
been done by hand.
Photograph 2 shows an Enigma machine which is quite portable
so can be used in the front line.
Photograph 3 shows the front of a Bombe machine and all the dials that
were set up to start a run. Hundreds of
female service personal ran these noisy, hot machines and gave them their own
names.
Breaking the overall system and then finding the keys to
each day’s encrypted messages gave the Allies key tactical information although
there were times when it took a few days to break into the codes. However Bletchley Park’s success meant that
the commanders in North Africa knew both Rommel’s plans in the latter stages of
that war and also knew which supply ships were carrying arms and fuel and so
could be bombed.
It was critically important that the enemy did not get any
inkling that the British had broken Enigma and so ships could only be attacked
that had been spotted by aerial reconnaissance.
De-coding the U-Boat Enigma messages was one of the key
elements in beating the wolf packs and winning the Battle of The Atlantic but
there was a long period of several months in 1942 known as the Shark Blackout
when the Germans introduced a fourth wheel and other changes to the Enigma
enciphering system and it took BP many stressful and worrying months before the
codes were broken again.
Incidentally Alan Turing was a true mathematical genius who also
helped in the invention of the first computer at Bletchley and his theories
started the modern thinking about machine intelligence. His tragic death by suicide robbed the world
of a brain that would have moved forward machine design in so many ways.
There is a statue of Alan at the centre (photograph 4).
The number of incredibly clever men and women who built
Bletchley Park’s intelligence systems are too many to mention. Photograph 5 shows some of the key code
breakers:
Dily Knox, Alan Turin, Peter Twin, Gordon Welchman, Frank
Birch and Hugh Alexander, John Herivel was another important code breaker.
As well as the extremely clever mathematicians and other
cryptanalysts there were a number of key managers and leaders.
Admiral Hugh Sinclair established Bletchley. Alistair Denniston was the ‘chief officer’
with Edward Travis as his deputy.
Another example was Eric Jones – from a Macclesfield family
who ran textile business. Hut 3 was
responsible for assembling and distributing German Army and Luftwaffe
de-cyphered information. There was internal in-fighting amongst the
management. Squadron Leader Jones was
sent in from the RAF to investigate. He
identified the management issues, he was then put in charge of it and it
improved vastly.
The organisation of Bletchley’s operation was based on
separate ‘huts’ and no one knew what the next hut did.
The secrecy led to the difficulty of getting resource as
Bletchley’s role was so secret no one in Whitehall knew about it. Following a visit by Winston Churchill;
Gordon Welchmann, Alan Turin, Stuart Milner-Barry and Hugh Alexander wrote to
Churchill about this lack of resource stopping them decoding and Churchill
wrote the famous ‘Action This Day’ on
the note instructing Whitehall to provide the money required.
But Enigma was only one encyphering system BP needed to
crack. The German High Command used a
system called Lorenz and the Allies did not know how that worked at all.
Lorenz messages were created by an encyphered tele printer
system. John Tiltman and Bill Tutte
cracked an encyphering system that no one understood, working on a machine no
one had seen, giving an ‘impossible’ number of combinations – 1.6 million,
billion of them.
The level of
information in Lorenz decrypts were so significant that the Allies called these
‘ULTRA’ as they gave strategic information.
Once the theory and principles of Lorenz were understood Bletchley
still had a problem of how to de-cypher messages quickly. There were a number of key figures who worked
out an electro-mechanical way of speeding this up and the machine that they
invented was called the Heath Robinson as its design reflected those zany
machines. However another incredibly
clever man from the General Post Office (GPO) called Tommy Flowers , who worked
for the exceptional Gordon Radley at Dollis Hill, devised a more reliable ‘electronic
programmable machine’ to help in deciphering Lorenz. This is Colossus, the first ever computer driven using valve technology. Photograph 8 shows part of the Heath Robinson
machine and also Colossus.
As well as ‘decoding’ these systems and getting German
messages into ‘plain German’, BP went on to develop many other aspects of
intelligence gathering. At its peak
there were over 9.500 staff at the Park and I can only touch on a few of them.
Gordon Welchman made sure Bletchley Park developed traffic
analysis on sources of traffic and the volumes as this showed where activity
was highest and, coupled with ‘decrypts’ this could guide the gathering of
information to give to Allied Commanders a picture of enemy activity.
BP also kept a comprehensive manual meta-data system of
cards referring to every message that had been decrypted, its time and date and
who the messages were to and who had sent them in addition to the subject.
The best way of concluding this short overview is to repeat
what General Eisenhower said – the work of the intelligence services probably
shortened the war by two years.
The exhibitions displayed at BP are comprehensive and
fascinating. There is even one about the
use of carrier pigeons and the father of one of our members, Alan Humphries,
established this exhibition.
This article skims the surface of what Bletchley Park
achieved. If you want to read more there
are two recommended books:
Bletchley Park and D-Day by the Park’s historian David
Keynon.
Michael Smith’s ‘Station X’ that describes all the work done
at the Park
