The Life and Achievements of Tommy Flowers
Early Life
Life at Bletchley Park
Post-War Life
Thomas Harold Flowers (Tommy Flowers) was
born to a working class family in Poplar in
London’s East End on 22nd December 1905.
From humble beginnings, Tommy Flowers
proved himself to be extremely gifted and
mathematically minded from a young age;
having gained a scholarship from a technical
college he was able to remain at school until he
was sixteen. He then acquired a four year
internship in mechanical engineering at the
Royal Arsenal in Woolwich, where his drive for
learning led him to take night classes at the
University of London where he earned a degree
in electrical engineering.
Tommy Flowers first became involved in the
codebreaking activities at Bletchley Park in 1941, when
he and Gordon Radley, Head of the GPO Research
Station at the time, were asked to help with
developments surrounding the mechanical machine
Alan Turing had created to crack the Enigma codes - the
Bombe. Bletchley Park requested that Flowers and
Radley make a relay-based machine to be used in
conjunction with the Bombe to speed up the process of
daily code breaking. This machine was ultimately not
used, however Flowers had impressed Turing with his
work and ability.
After the war, as the Cold War environment took hold, secrecy
became the immediate priority for all those involved at Bletchley
Park. It was ordered that the Colossus machines be dismantled and
all documentation relating to them be destroyed. All those who had
been involved in the secrets at Bletchley Park were forbidden to
speak of their roles there to anyone. This secrecy meant that in
1946, when the American ENIAC (Electronic Numerical Integrator
and Computer) was created and branded as the ‘World’s First
Electronic Programmable Computer’ Tommy Flowers had to remain
silent, despite being the man to whom true credit is due .
During the 1920s, as the telephone network became more automated,
exciting developments were taking place in the telephony engineering
industry, and, as a result of this the General Post Office (GPO) was
looking to expand its engineering staff. In 1926 the GPO held a
competition to recruit engineers, Tommy Flowers entered and came
first. Upon joining the GPO Flowers’ obvious technical flair was quickly
noted and it was not long before he was promoted to work on more
advanced projects. An early project saw Tommy solve the problem of
transmitting ‘telephone dialling pulses’ over long distances by using
‘thermionic valves’ to convert the dialling pulses into voice-like signals
that could easily be amplified – breakthrough innovation at the time!
Tommy Flowers was approached again in 1943 on Alan Turing’s recommendation, this
time to work on the more complex Lorenz S740/42 code. The Lorenz code was a new,
superior and more secure cipher that the German High Command had begun using in
1941. Messages sent using the Lorenz machines were often of more use to the allies
than those sent using Enigma. Max Newman, a Cambridge mathematician working at
Bletchley Park, had noted the potential for mechanisation of a method devised by Bill
Tutte in 1941, and had designed the Heath Robinson machine, to implement this
method. It was this machine that Flowers was asked for help with. However, Flowers
quickly realised that Bletchley Park were wasting their time with the Heath Robinson
machine, which was a slow and unreliable electro-mechanical machine which relied on a
two tape mechanism, which caused many problems and frequently got stuck or ripped,
slowing down the process. Thus, whilst working on the Heath Robinson, Flowers began
considering the possibility of a new electronic, programmable machine.
1941- 1945
1905- 1930
1930- 1941
Life at
Dollis Hill
Tommy Flowers was moved to the GPO Research Station at
Dollis Hill in North London in 1930, where he became Head
of the Switching Department. Tommy Flowers himself
attributes the eventual creation of Colossus in part to his
work at Dollis Hill. Flowers began investigating the high rate
of failed calls from automatic exchanges, and this led him
to become interested in the use of thermionic valves as
switches, an alternative to the then universal electromagnetic switches of the day. By 1939 Tommy was
convinced that he could prove that an electronic equivalent
could be made of any electromechanical switching or
processing machine.
In 1948 Tommy Flowers returned to work full time at the GPO, resuming his role as Head of the
Switching Department. During the 1950s the GPO was tasked with designing ERNIE (Electronic Random
Number Indicator Equipment) for the launch of premium bonds and it was Tommy Flowers, working
with Henry Fensom, who built and designed the machine. Throughout his post-war life at Dollis Hill,
Tommy remained preoccupied with his idea for an electronic telephone exchange. However Tommy
was constantly confronted with problems as the National Secrecy Act restricted what he could say
when trying to bring his knowledge to bear on new challenges. The confinements of the secrecy act got
in the way of Tommy’s projects right up until he left the GPO in 1964, and again at STC (Standard
Telephone and Cables) until he retired in 1970. However, although Tommy was not able to lead the
successful project to make an electronic exchange, his legacy continued after he left the GPO when in
1968 the first electronic exchange, ‘The Empress’ exchange, was installed in London. This pioneering
work set the blue-print for telephone switching around the world and many of the engineers leading
this important world first were a product of Tommy’s research team and learnt their art through
Tommy’s inspirational leadership.
1943- 1945
Colossus
Tommy Flowers started considering plans for a new machine, which would be known as Colossus, in March 1943.
His research at Dollis Hill before the war had taught him that, contrary to popular belief, electronic valves were
reliable if left on continuously and not moved and he was certain that this technology could provide the reliable
and high-speeds needed for code- breaking. However Tommy faced problems, having worked predominantly
alone at Dollis Hill, he had little proof or authority that his ideas were correct. The machine, if practical, would
immediately eliminate the technical problems caused by the mechanical tape stage of the Heath Robinson
system because it only required one tape, the second being replaced with electronically generated patterns
which would be read using thermionic valves. This would make the process faster and more reliable, removing
the problems of synchronisation and accidental ripping of tapes, however it would also require 1500 valves, a
scale not previously considered practical in a reliable machine.
The Bletchley Park management were initially very sceptical of Flowers’ idea and would not commission him to create the machine due to fears over
reliability, resources and how long it would take to build. However, he was encouraged by the Top Brass to build the machine on his own anyway if he
wanted to. Thus with the support of Gordon Radley and the GPO, Tommy and a close-knit team of around fifteen GPO engineers, began building the
machine at Dollis Hill. The GPO provided him with significant resources, however Flowers also frequently had to fund parts of the machine as well and it is estimated that he spent about £1000 of his own money building Colossus 1.
Building Colossus was given total priority by the team and by 8th December 1943, Colossus was complete and working at Dollis Hill. The machine was
moved to Bletchley Park in January 1944, where it was given the name ‘Colossus’ due to its size and it successfully carried out its first job on 5th
February 1944. Bletchley Park were amazed by the machine which reduced the time it took to break the Lorenz code from weeks to hours. More
machines were immediately commissioned and by the end of the war there were ten Colossi decoding information at Bletchley Park and an eleventh
in production. By D-Day, June 1944, Bletchley Park had two running Colossus machines, and these machines had a monumental impact on the
success of the D-Day landings. The codes intercepted and decoded by Colossus were able to inform the allies where to strategically place troops and
importantly to confirm that Hitler had followed the deception laid by the allies that the attack would take place in Calais. By affirming that Hitler was
not expecting an invasion in Normandy, Colossus essentially confirmed the go ahead for D-day. By the end of the war the British were thought to be
decoding 90% of the messages sent by Lorenz code and it has since been said that Colossus was responsible for shortening the war by two years.
1970- Present
1945-1998
Recognition
After the war the official secrets act meant formal
recognition was limited. Tommy Flowers received an
MBE for his wartime work and a modest £1000, which,
incidentally was not enough to cover his personal
expense in creating Colossus 1. However as the Official
Secrets Act has started to relax, the truth about
Colossus and the work of Tommy Flowers has begun to
emerge, and people are beginning to recognise him as
the brilliant wartime hero and inventor that he was.
On 12th December 2013, 70 years after Colossus was
created, BT Labs at Adastral Park, honoured the legacy
of Tommy Flowers with a bronze bust. It is likely that as
the secrets of Bletchley Park continue to be revealed,
the work of Tommy Flowers will come to wider critical
acclaim and his truly remarkable contribution to
engineering and his impact on the history of WW2 will
be recognised.