Professor Tom Kilburn CBE FRS – a Personal View of a Remarkable Man

A Dewsbury born mathematician and computer scientist, who was involved in the development of five computers of great historical significance, including the first stored-memory computer, the “Baby”, over the course of a 30-year career. Includes interviews with his pre-war friend and fellow footballer, who happened to be the author’s father.

Early years

Tom Kilburn by Bassano Ltd 8th April 1965
© National Portrait Gallery, London (CC BY-NC-ND 3.0)

I grew up knowing about Tom Kilburn. He was born at 111 Town Street, Earlsheaton, Dewsbury, on 11th August 1921, just round the corner from where I was brought up. Tom’s father was a clerk at Mark Oldroyd’s woollen mill and later became Company Secretary.

An intelligent boy, Tom was educated at the Wheelwright Boys Grammar School (WBGS), but in those early years, nobody could have predicted the enormous role that he would play in the world of wartime and post war technology and the development of the world’s first stored memory computer. In the late 1930’s he was just another football-mad teenage boy who enjoyed stamp collecting, dancing and playing the piano, which he did rather well. He happened to be good at chemistry and mathematics too.

That’s when my Dad (Harold Archer) first knew him, in the late 1930s. Dad, two years Tom’s junior, joined the Ebeneezer Youth Organisation (EYO), in Dewsbury Town Centre, where he met Tom and they soon became good friends.

An EYO member called Irene Marsden taught Tom and Dad ballroom dancing…and Tom taught Dad to play the piano (well, after a fashion!). Both young men had bikes and they both played in the church football team, Tom as “centre forward” and Dad as “inside right”. Their friendship developed and later involved Tom’s younger sister Joan, who was just a year younger than Dad and Tom’s wife-to-be, their dance teacher Irene (Rene). Attending dances together at Dewsbury Town Hall on a Saturday night would come next.

Left to right: Cliff, Harold and Tom on Blackpool Central Pier, the last week of July 1939 on their way to the Dance Hall.

One day in the summer of 1939, Tom asked my Dad how far he could cycle…they agreed they could cycle to Blackpool so, when “Dewsbury Feast Week” came, when the mills closed for a week, Tom, Dad and another friend, Cliff, sent their luggage on ahead by train and set off at 8am on 22nd July to cycle about 75 miles in the day to Blackpool. They spent a week there in digs in the Hornby Rd area…and their holiday involved dancing at the Dance Hall on Central Pier and much more dancing at the Winter Gardens and the Tower Ballroom. Only five weeks later, war would be declared and that would occupy Tom and Harold in very different ways.

Educationally, the young men were very different. Dad had also passed the grammar school entrance exam two years after Tom but, in the mid-1930s, his parents couldn’t afford the uniform and books to send him to the grammar.

Consequently, Dad was to attend Eastborough Elementary School in Dewsbury, where he became Head Boy and left school, aged 14, in 1937.

By 1938, Dad was working as a spinner at Aldham’s Blanket Mill and Tom was excelling in maths and science at WBGS.

At this time, Tom was being encouraged by his headmaster to pursue mathematics rather than chemistry and he won a scholarship to read mathematics at Sidney Sussex College, Cambridge, which he entered in 1940. Tom took a 2 year war degree (cut from three years to two, so that students could be out in the working world quicker) and graduated in 1942 with a First Class Honors in Part I of the Mathematical Tripos and in the preliminary examination for Part II.

In 2014, when my father was 91, I made some video recordings of him talking about Tom Kilburn. The first one talks about their teenage years.

WW2 Tom and Harold are “Called Up”

In late 1942, CP Snow (novelist, scientist, and government administrator) visited Cambridge to recruit students for “unspecified war work”, so after leaving Cambridge, Tom enrolled in crash courses in electricity, magnetism and electronics before being posted the Government’s Telecommunications Research Establishment (TRE) at Malvern, to work under fellow scientist Freddie Williams. There, they worked together on the development of Airborne Radar Systems. Tom was later reported to say:

It seems silly, but if I could have joined the RAF as a pilot, I would have done that, but I was relegated to navigator or some such, and that was not quite so appealing. It sounds egotistical but I like to lead. I like to be in charge and I didn’t fancy the idea of being driven and crashed by some other character. I wanted to do my own driving and crashing. It’s on these sorts of whims that life is founded – it’s not through any profound thought is it? You take advantage of what’s there at the time.

Interview with Tom Kilburn; Bowker & Giordano, 1993
Harold in c1942
My father, Harold, had also been called up in 1942, but he was to serve in the Royal Army Service Corps, driving ammunition trucks across Europe after the D-Day invasion.

Dad was involved in the relief of Bergen-Belsen Concentration Camp then served in the Military Government in Hamburg after the end of the war, returning to England and to Dewsbury in 1947. 

Now his glowing army reference enabled him to stop working in the mill and obtain work in the offices of the Yorkshire Woollen Transport Co Ltd, where he became head of their cash office.

Tom and Harold lost touch until after the war and went on to lead very different lives afterwards. 

WW2 Research in Computing

During World War II, British code-breakers at Bletchley Park, led by Alan Turing, developed a machine which eventually cracked the German Enigma code. It was named “the Bombe”. Another machine, developed at Bletchley by Tommy Flowers and others was completed in 1944 and named “Colossus”.

Regarding Colossus, its predecessor “Tunny” also known as Heath Robinson, was built to a specification created by Max Newman and a prototype built at Bletchley Park. Tommy Flowers (and others) developed this into “Colossus” for which Flowers is rightly credited. It wasn’t strictly programmable in the modern sense, as it only derived the key to a Lorenz code.

Tim Banks, MOSI Manchester

The US-built ENIAC (Electronic Numerical Integrator and Computer), completed in 1945, calculated artillery tables for military use. It was set up using cables and wall sockets. Although the ENIAC was similar to the Colossus, it was much faster and more flexible. But these machines could not store programmes.

Post War Research in Digital Storage

Williams-Kilburn Tube at Manchester Science and Industry Museum

The next step for Williams and Kilburn was to build a new machine, using the technology developed for Second World War radar and communications equipment. Their aim was that it would store programmes. Such a system was essential to the progress of electronic digital computers and this is where Tom would excel.

In 1946, Williams and Kilburn invented a type of digital storage in the form of a charge on a cathode ray tube (CRT). The charge leaked away in a fraction of a second, so the two colleagues developed a method of reading and rewriting the charge continuously so that the information could be stored. The CRT storage system became known as the Williams Tube (more recently known as the Williams-Kilburn Tube).


In 1947 Freddie Williams became Professor of Electro-Technics at Manchester University and Tom Kilburn was seconded to work with him there. Williams had many duties as Professor of the Department, leaving Tom and his assistant to work full time on the memory project and just “popping in” occasionally when time allowed.

After much trial and error, CRT data storage was further developed and, by the end of 1947, they had managed to store 2,048 bits on a special 6 inch diameter CRT supplied by the General Electrics Company.

Tom now built the “Small-Scale Experimental Machine” at Manchester. Two factors were important in this achievement. First was Tom’s enthusiasm for building things – he would advise students, when they became bogged down in theory…

Go away and make something, even if it’s a mistake!

Tom Kilburn

Second was the availability of the necessary components – particularly the CRTs – and valves obtained from TRE, Malvern.

In an interview, Tom described his laboratory as being 7 metres square and with a wooden floor and tiled walls. The place became very grimy but the experimental machine wasn’t cleaned in case the cleaners damaged a part. The parts were possible to come by from TRE but there was no actual money available for the project. Therefore they couldn’t afford to install air conditioning and had to work in temperatures up to 100 degrees (F) and it was very uncomfortable to work in.

The Small-Scale Experimental Machine built at Manchester was called “Baby.” Regarding the baby and its name, Tim Banks from the Manchester Museum of Science and Industry says:

I have two theories about how it got the name. One is the one I use with the younger visitor – that BABY was a small machine compared with other computing machines of the period. ENIAC was massive! The other explanation comes from Bletchley Park. On a visit there… I spotted a sign in Hut 8 (Newman’s Hut) in which a worker there during the war described being on night shift and left to monitor a small machine they had running – “I was left minding the BABY” she said. Given that a number of Bletchley Park people moved to Manchester University (Newman and Turing for example)  you could imagine how the name might have come with them to Manchester.

Tim Banks, Manchester Science and Industry Museum

It was a pretty big baby though – it was 17 feet (5.2m) in length, 7 feet 4 inches (2.24m) tall, weighed almost a ton and filled a small room.

Importantly, it was the first machine that had all the components regarded as characteristic of a basic modern computer. It was also the first computer in the world to run a program electronically stored in its memory, rather than on paper tape or hard-wired in.

First Programme

Baby’s first programme, written by Tom, first ran on 21st June 1948. He is said to have written this on his train journey between Dewsbury and Manchester. This programme became the first example of computer software and the development of the Baby marked the beginning of the digital revolution, almost 200 years after the Industrial Revolution had been led from the same city.

Freddie Williams said afterwards:

A programme was inserted and the start switch pressed. Immediately the spots on the display tube entered a mad dance. In early trials, it was a dance of death leading to no useful result and, what was worse, without yielding any clue as to what was wrong. But one day it stopped, and there, shining brightly in the expected place, was the expected answer. It was a moment to remember. Nothing was ever the same again.

Professor Freddie Williams

Further Developments in Computing

When interviewed in 1982 for the North-West Sound Archive, Tom said:

For a while we wondered what the computer could be used for in any practical sense. In fact one of our assistants left saying he couldn’t see a future in computers.

However, from the Small-Scale Experimental Machine, the much more sophisticated and capable “Manchester Mark 1” was built. By this time, Professor Williams had moved on to other interests in Electrical Engineering, leaving Tom Kilburn to work with Ferranti to develop a commercial version of the computer. He was assisted by wartime code-breaker, Alan Turing, who was also working in mathematics at Manchester University, though it has been said that they “didn’t get on”. Their first commercially available computer, the “Ferranti Mark 1” was based on the Manchester Mark 1.

In 1960, my husband, John Widdall, had begun an Undergraduate Apprenticeship with aeronautical company A V Roe & Co (AVRO). This involved spending a year with AVRO, before doing a three year degree course at Manchester University. He said:

In 1960, at the start of my Undergraduate Apprenticeship with A V Roe & Co, I was thrown in at the deep end and spent some time learning to program the Ferranti Mk 1. Unfortunately, computing time was scarce and little time was available to try out my own programs. Because of the limited life of valves, replacement was a frequent and time-consuming job resulting in significant “down time”.

John Widdall 2020

Manchester University Department of Computer Science

Tom’s team continued to work on the development of computers, using transistors and magnetic storage and many of Tom’s ideas for improvements became world firsts.

Under Tom’s direction, the team developed several other machines including “Atlas”, commissioned in December 1962. Considered at the time to be the most powerful computer in the world, it was said that one Atlas computer represented one half of the UK’s total computer capacity.

In 1964, Tom Kilburn founded Manchester University’s Department of Computer Science, becoming its first Professor and keeping the University at the forefront of computer design over the next 20 years. My husband was to meet Tom Kilburn in the same year, something about which my Dad was very pleased when he found out. John said:

In my final year at Manchester (1964), I recall meeting Tom to ask him to sign my proposal form for membership of the IEE. I had decided to read Physics even before applying to A V Roe & Co, but I also had an interest in Electronics so chose the “Electronics option” as it was called, in my third year at Manchester. This involved spending about half my lecture time in the Electrical Engineering Department and I decided to apply for membership of the Institution of Electrical Engineers (as it then was).

Requiring a proposer and seconder who were already members, I gingerly knocked on the door of Professor Kilburn’s office, as he was a Fellow of the IEE. After a short interview, I had my proposer’s signature and was able to find a seconder at AVROs.

Although at that time a team was working on the Atlas computer, as an undergraduate I was only able to have a quick look at it.

John Widdall 2020

In 1966, Tom’s team started his last major project, known as “MU5” for which the University was granted £630,000 by the Science Research Council. MU5 was the only Manchester computer which did not have a direct commercial counterpart, but many of its concepts and architecture formed became the basis of the ICL 2900 computer series of 1975.

A building at Manchester University, opened in 1972, was named “The Kilburn Building” in Tom’s honour.

Later Life

In the second video, Dad talks about Tom, the Baby and their meetings in later life.

Tom remained modest and unpretentious and preferred not to dwell on the importance of his own contributions to Computer Science. He had moved to live in Manchester and continued to enjoy family holidays in Blackpool. He never sought the limelight or made much money from his inventions and he remained a family man with a passion for Manchester United FC and music, just like my Dad!

Two weeks after his wife Irene’s death in 1981, Tom retired and he continued to live alone in Manchester in the family house that they had shared for decades.

In 1998 Tom unveiled the fully functional replica of “The Baby” at the Manchester Museum of Science and Industry, which I had the privilege to photograph some years ago (see gallery above).

Though Dad and Tom had moved apart and led very different lives, they kept in touch through Joan and very occasionally met when Tom was in Dewsbury, when they talked of old times. The photographs below show Tom, Dad and Tom’s sister, Joan, in Dewsbury, on the 50th Anniversary of the Baby.

Professor Tom Kilburn died at Trafford General Hospital on 17th January 2001 from pneumonia, following abdominal surgery, aged 79.

He did not own or use a personal computer and said he could never have foreseen how they would intrude into everyone’s everyday lives.

Dad outlived Tom by 13 years and died in September 2014, aged 91. He always remembered his friend Tom and talked about him with fondness, pride and respect.

Tom Kilburn 1921-2001
Awards and Achievements

  • 1940-1942 BA and MA, Mathematics, Cambridge University
  • 1948 PhD Manchester University
  • 1953 DSc Computer Research, Manchester University, 1953
  • 1954 Fellow IEE
  • 1960 Professor of Computer Engineering Manchester
  • 1964 Professor of Computer Science, Manchester
  • 1965 Fellow of the Royal Society
  • 1971 IEEE Computer Society W Wallace McDowell Award
  • 1973 the British Computer Society IT Award
  • 1973 Commander of the Most Excellent Order of the British Empire (CBE)
  • 1974 Distinguished Fellow of the British Computer Society
  • 1976 F Eng founder member of the Fellowship of Engineering
  • 1978 Awarded the Royal Medal of the Royal Society
  • 1979 Awarded an Honorary Doctorate of Science from the University of Bath
  • 1982 The IEEE Computer Society Computer Pioneer Award
  • 1983 The Eckert-Mauchly Award, ACM & IEEE Computer Society
  • 1983 The Mountbatten Medal
  • 2000 Appointed a Fellow of the Computer Museum History Centre