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Docket #:2024-03

This is a draft proposal, that has not yet been submitted. To submit this proposal, click on the edit button in toolbar above, indicated by an icon displaying a pencil on paper. At the bottom of the form, check the box that says "Submit this proposal to the IEEE History Committee for review. Only check this when the proposal is finished" and save the page.

To the proposer’s knowledge, is this achievement subject to litigation? No

Is the achievement you are proposing more than 25 years old? Yes

Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes

Did the achievement provide a meaningful benefit for humanity? Yes

Was it of at least regional importance? Yes

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes

Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes

Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes

Year or range of years in which the achievement occurred:


Title of the proposed milestone:

The Colossus Computer 1944

Plaque citation summarizing the achievement and its significance:

The first Colossus code-breaking computer was delivered to this building in January 1944. Designed by Thomas H. Flowers of the British Post Office Research Station, it helped obtain intelligence in the process of deciphering secret radio messages transmitted between Berlin and German Commands across occupied Europe, thereby shortening World War 2 and saving many lives. As the first large-scale computing application of digital electronics, Colossus anticipated the modern computer.

200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.

The Colossus code breaking machines were developed to attack the World War 2 German Tunny cipher used to encrypt radio traffic between Berlin and the major German Army Commands across occupied Europe.

Breaking the Tunny cipher was beyond what could be achieved by manual techniques or by electromechanical machines.

Deciphering messages using Colossus made one of the most significant contributions to victory in Europe, due to the strategic nature of the intelligence gained.

Colossus was developed by a team led by Tommy Flowers from the British Post Office research laboratory at Dollis Hill in London.

The first Colossus was delivered to Block H at Bletchley Park in January 1944, rapidly followed by a further nine machines.

For its time, Colossus was an electronic tour-de-force. It used circuits for counting and Boolean algebra functions to perform statistical calculations on encrypted messages. Input was via a 5,000 character per second photoelectric paper tape reader and output to an online teleprinter. Containing over 1,500 thermionic valves (vacuum tubes), Colossus was significantly larger than any other contemporary electronic device and ran continuously 24 hours a day, seven days a week. It was programmed using switch panels and jack leads to set up the desired computations. In many respects Colossus anticipated the modern electronic digital computer.

There is controversy around “the first computer”. We are seeking recognition of Colossus as the first use of large-scale digital electronics to perform calculations and for its contribution to the Allied victory in 1945.

IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.

IEEE Computer Society, IEEE Communications Society

In what IEEE section(s) does it reside?

United Kingdom and Ireland

IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):

Unit: United Kingdom and Ireland
Senior Officer Name: Paul Cunningham (Chair)

IEEE Organizational Unit(s) arranging the dedication ceremony:

Unit: United Kingdom & Ireland
Senior Officer Name: Paul Cunningham (Chair)

IEEE section(s) monitoring the plaque(s):

IEEE Section: United Kingdom and Ireland
IEEE Section Chair name: Paul Cunningham (Chair)

Milestone proposer(s):

Proposer name: Dr Andrew Herbert OBE FREng
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):

Block H, Bletchley Park, Milton Keynes MK3 6EB, United Kingdom

51.9984° N, 0.7437° W

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. Block-H Bletchley Park, Bletchley UK. Original location of Colossus machinesin 1944-5 and today home of the UK National Museum of Computing (TNMoC). Building owned by the Bletchley Park Trust but outside the perimeter of their "Home of The Codebreakers" museum. Publically accessible from combined entrance to Bletchley Park via direct access road to TNMoC.

There is an IEEE Milestone plaque on the "mansion" building at the centre of the codebreakers' museum, celebrating the World War 2 code breaking and intelligence achievements of Bletchley Park.


Are the original buildings extant?

Block H is the original building that housed the Colossus machines and has UK "listed grade 2" status as a historically significant building, due to its World War 2 history.

Details of the plaque mounting:

On outside of building near main entrance.

How is the site protected/secured, and in what ways is it accessible to the public?

Bletchley Park is a secured site with entrance via a controlled gate. Visitors are able to enter via the main gate and drive/walk to H-Block without payment of a fee. The Bletchley Park Trust web site gives opening times for the park. Generally open all year during day time hours, except for 24th, 25th and 26th December.

Who is the present owner of the site(s)?

Bletchley Park Trust. The UK National Museum of Computing occupies Block-H as a tenant of the Trust.

What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include justification here. (see section 6 of Milestone Guidelines)

What obstacles (technical, political, geographic) needed to be overcome?

What features set this work apart from similar achievements?

Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.

Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to Please see the Milestone Program Guidelines for more information.

Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).

Please recommend reviewers by emailing their names and email addresses to Please include the docket number and brief title of your proposal in the subject line of all emails.