Alone with Colossus


Its name is legend, whispered with reverence by geeks around the planet. Approximately the size of a large van, Colossus is the world’s first programmable computer, originally deployed at Bletchley Park to tackle the German High Command’s Lorenz Cipher during WWII. Indeed, this sizable collection of valves, wires, and assorted other gubbinry  is the wellspring from which our technological age gushed forth. Designed by unsung hero and electrical engineering genius, the late Tommy Flowers, erstwhile of Her Majesty’s Post Office, it is the grandsire of all computers. 

And, not for the first time, I’m standing next to it.

This is my third visit to The Colossus Gallery at the National Museum of Computing in Bletchley. I’ve started gravitating to this place whenever I’m anywhere near the area, drawn to return by the proto-computer’s monumental presence, by its sheer sense of deep computing history. Today, however, is different from my previous two visits. For its gallery is empty, devoid of onlookers, of visiting geeks taking selfies, of dumbstruck programmers mumbling to themselves about pilgrimages, and of enthusiastic volunteer guides reciting the Colossus 101 History Lesson.

Today I am alone with Colossus.

I stand in awe, truly hearing the computer for the first time, undisturbed by the distractions of other humans in the room. Its whirring, clicking voice is mesmerizing and carries a curiously ‘alive’ quality. This Strange Engine undoubtedly personifies the ‘Spirit of Computerdom’ and, for now at least, that Spirit is speaking solely to me. I stand and listen.

An indeterminate time later I resurface from my reverie. I am still alone, so I use the opportunity to take photos of Colossus from all sides. This takes some minutes, but when I’m finished the space around me remains deserted. I unpack my Ricoh Theta, fix it to one of my Gorillapods, and start shooting 360° panoramas all around the enormous machine.

(Mouse-Grab Images and drag to look around the gallery)

Throughout the entire process I remain alone in the gallery and, after I finish, I return to my contemplation of this amazing apparatus, once again lulled by its soothing tones.

Colossus Paper Drive

Finally I hear voices approaching from the Tunny Gallery down the hall. I check my watch. Over ten minutes have passed since I entered the room. I pack away my cameras and exit quietly. My private audience with Colossus is over.


The unit on display at the National Museum of Computing is, of course, a reproduction. Nevertheless, it is a copy painstakingly constructed from original sources, undertaken by electronics engineer Tony Sale and supervised by Tommy Flowers himself, prior to his death in 1998. You can read more about the reconstruction project here.

The 19 months between its initial deployment in February 1944 and the end of the War (VJ-Day), saw ten Colossus units being constructed at Bletchley. Their contribution to the Allied war effort is basically incalculable, as these machines were the only means of cracking a reputedly unbreakable German cipher.

At the end of the war, all but two of the computers were dismantled, their components either reused elsewhere or destroyed. The two remaining units were moved to GCHQ in West London and remained in use until 1960, when they too were dismantled, and all remaining blueprints [supposedly] destroyed.

The story may well have ended there, with Colossus vanishing from history altogether. 

With the declassification of wartime documents in 1975, however, rumor of the machine began to resurface, and by the late seventies the computer's existence had become public knowledge. By 1991, Tony Sale was convinced that a rebuild of Colossus was not only possible, but that it was essential in order to preserve a pivotal element of Computing History.

During his initial quest to contact Colossus' remaining creators, Sale found that many of them had retained technical documents and schematics, and by 1993 all necessary documentation and engineers were in place to begin reconstruction in earnest.

Following a three year build process, Colossus finally returned to life on June 6th 1996 with a 'Switch-Throwing Ceremony' attended by the Duke of Kent and by Tommy Flowers himself.

Since that day, the giant computer has been clicking away in Bletchley Park's Block H, the site of the original Colossus Unit #9 during the war.


It's nigh impossible to convey the sheer sense of awe I experienced, left alone with this legendary computer for such an extended time. The gallery's atmosphere is palpable, even with a dozen or more visitors clustered around Colossus. When the room is empty that atmosphere assumes a positively intense nature.

I am rarely speechless, but after leaving the Colossus Gallery I was unable to utter a word for a considerable while.


Find out more about Colossus through this link.

Ph'nglui mglw'nafh Cthulhu R'lyeh, wgah'nagl.