So, in mid-1950, the computer age had begun to grow up. Of the 6 machines that had been built, 4 were British. But who had been the greatest individual achiever in those early years?

There will be several opinions on this subject, but Tommy Flowers must be high on the list. He had the vision to see that a machine with 1,500 valves could be built and operated to provide continuous reliability. When Bletchley Park declined to back the expenditure, he persuaded the Director of the Post Office Research Station to take responsibility for it. With his colleagues he built COLOSSUS in 11 months and COLOSSUS II in 3 months. Both machines operated from day one and both produced results of the highest importance for world history. It is seldom the case that the first prototype for hundreds of millions of machines fulfils one of the most vital practical tasks of all.

As for the greatest influence on the future, it was John Mauchly and Presper Eckert, together perhaps with John von Neumann and Herman Goldstine who must be selected. The ENIAC was the first true number cruncher from spring 1948, the first computer in a modern sense, and the practical origin of the crucial stored program concept from which a great industry sprang. It might have been otherwise if COLOSSUS had not been so shrouded in secrecy, but the early history of computing is full of “ifs”. Mauchly and Eckert’s achievement was the greater because they started off with the disadvantage that they, and the Moore School, were poorly regarded by the US scientific community leaders.

Yet despite the undeniable genius of the mathematicians and engineers who designed and built the COLOSSUS and ENIAC, neither could have been built without funding and support. In this regard then, there are two men who stand out as having had the foresight to understand how necessary these machines were. They had the faith to back their engineers financially and logistically and the courage to do it against a background of war, the incredulity of ‘educated’ men and unprecedented leaps of engineering and scientific faith which were more than likely to result in failure. Those two men are: (Sir) Gordon Radley, wartime head of Dollis Hill who backed and cleared funding for the COLOSSUS, and Colonel Paul Gillon of the US War Department’s Ordnance Division, who supported the development of ENIAC.


Finally it was Wilkes, Williams and Kilburn who first built the computers to resemble more closely what we know today. However, they had two advantages over Flowers, Mauchly and Eckert.  Firstly, they already knew that a machine with many hundreds of valves could be operated successfully over long periods.  Secondly, they had the advantage of being able to draw on much greater sources of electronics research and knowledge through the Radiation Laboratory at MIT (in the USA), the Telecommunications Research Establishment (in the UK) and the Admiralty Signal Establishment (also in the UK).

Paul Gillon (right)

Sir Gordon Radley (front)