From: Jon Agar <>
Date: Fri, 7 Jun 1996 22:15:58 BST
Subject: Colossus

----------forwarded from shothc-l---------

Date: Fri, 7 Jun 1996 11:21:31 +0100
        Rosemary Lockie <>,
        "Michael R. Williams" <williams@CPSC.UCALGARY.CA>
From: (Brian Randell)
Subject: The Colossus Rebuild Project
Hi All:

Yesterday I attended the ceremony at Bletchley Park for the formal switching on
of the recreated Colossus computer. It was a glorious day, attended by about two
hundred people, many of whom had worked on code-breaking at Bletchley Park
during the war, and both Tommy Flowers who original designer of the Coplossus,
and Bill Tutte the cryptanalyst who first broke the Fish cipher.

The Colossus Rebuild Project is essentially due to one person, Tony Sale, who is
I'm sure uniquely qualified for such a project. He was for many years with M.I.5
(including a period as technical assistant to Peter Wright, of "Spycatcher"
fame/notoriety) and so has a very high security clearance, he is a real expert
on ancient electronics, he was for several years a Senior Curator at the Science
Museum, London, (where he led the project which got a Ferranti Pegasus and an
early Elliott computer operational again) and he has an unbelievable ability to
get things done. The document attached below is the press briefing for
yesterday's ceremony.

The recreated Colossus is remarkably authentic (not just in looks), though not
yet finished. (It was however complete enough yesterday to read encrypted
messages from the 5000 character per second paper tape, do some basic processing
using an electronic version of the Lorenz (Tunny) rotors, and output counts onto
an electromechanical typewriter - all *very* impressive.

There are also a whole series of rooms in which the various aspects of the
wartime work, from radio interception, through to processing and indexing the
results of the codebreaking are portrayed and explained. There is a Typex
machine, Naval Enigma, a Siemens Geheimschrieber and a Lorenz SR42 (Tunny)
cipher machine on display, plus lots of other artefacts - such is the extent to
which Tony Sale has been getting cooperation from Bletchley Park's modern

When in the mid 1970s I succeeded in getting the Colossus partly declassified,
and some photographs of it released, I never dreamt that, over twenty years
later, I would actually see a real - albeit recreated - one!



PS You will find a home page for the Colossus Rebuild Project at:

Dept. of Computing Science, University of Newcastle, Newcastle upon Tyne,
EMAIL =   PHONE = +44 191 222 7923
FAX = +44 191 222 8232  URL =


The Colossus Rebuild Project
Helping to save Bletchley Park by Tony Sale, FBCS.

The switching on of the rebuilt Colossus on Thursday 6th June 1996 by His
Royal Highness the Duke of Kent KG. Briefing notes. Colossus was the first
large electronic valve computer in the world and it was fully operational
in the Spring of 1944, helping to break the German Army High Command
messages enciphered using the Lorenz cipher machine. By the end of WW II
ten Colossi were operating in Bletchley Park, the home of Allied code
breaking operations. Each one of them used 2,500 electronic valves and they
represented a major technological triumph for British invention. Designed
by Dr Tommy Flowers and his team of engineers at the Post Office research
labs at Dollis Hill and manufactured at great speed they contributed
significantly to the war effort by the intelligence that they revealed
before and after D Day, 6th June 1944.

The Colossi were special purpose, high speed logic calculators of great
reliability. They were kept switched on and running 24 hours a day and
operated by girls from the Women's Royal Naval Service, the WRENS.

The very existence of the Colossi was kept a closely guarded secret and
unfortunately all but two of them were totally destroyed at the end of
1945. The reasons for this are still not clear. A blanket of silence
descended on everything to do with Bletchley Park and this has, until now,
prevented Colossus taking its rightful place as one of the greatest
achievements of British technology. It has also allowed the Americans, for
far too long, to claim that their ENIAC computer, which first ran in 1946,
was the first large electronic valve computer in the world.

The first revelations about Colossus appeared in 1970 when Jack Good, one
of the wartime code breakers, gave a brief description in a journal
article. This was followed in 1972 by further revelations by Donald Michie
another of the code breakers and then by the researches of Prof Brian
Randell. But even then Colossus was classified as secret and only a few
photographs and general details were allowed out.

In 1993 Tony Sale had just finished working at the Science Museum in London
restoring some early computers back to working order. Having studied all
the available meagre details about Colossus, he decided that given his
early career in valve electronics, his involvement with Ml5 and subsequent
long career in computing, it would be possible to rebuild a working

An approach to GCHQ resulted in all the hardware details about Colossus
being declassified and a further set of wartime photographs emerged from
GCHQ archives. Some of the original engineers were still alive, including
Dr Tommy Flowers, and they were all enthusiastic about such a project. Work
began in November 1993 to reproduce machine drawings from the photographs.
(All the original drawings had been destroyed in 1960). All attempts at
getting sponsorship for the project failed and Tony Sale and his wife
Margaret decided to put their own money into it in order to make a start
since, in view of the age of the original engineers, time was of the

By July 1994 all the gathering of Information had been done and the
construction phase of the project was inaugurated by His Royal Highness the
Duke of Kent KG in Bletchley Park on the 18th July. The Bletchley Park
Trust, of which Tony Sale is Museums Director, has kindly made space
available and the construction has taken place in the actual room in H
Block where Colossus number 9 stood in WW II.

Two years of hard work helped by an ever growing band of volunteers,
including some members of the Computer Conservation Society, and some
gratefully received financial donations has resulted in 90% authentic
rebuild of Colossus which will now be able to demonstrate its code breaking
feats of WW II.

His Royal Highness has kindly agreed to switch on Colossus at 10.00 am on
Thursday 6th June 1996, an auspicious occasion since it is the anniversary
of D Day for which Colossus helped to provide vital intelligence

For further Information contact Tony Sale on 01908 645001 or 01234 822788
or by fax on 01908 247381 or by email