27/03/1897-12/02/1958.

Douglas Hartree was an eminent Cambridge scientist noted for his contribution to a number of fields of study including early computing – as an example he was the first civilian to programme ENIAC - and played a crucial role in the collaboration between Cambridge University and J Lyons & Co in the development of the LEO computer. 

While working in Applied Mathematics at the University of Manchester, Hartree built his own Differential Analyser from Meccano and subsequent versions of the machine went on to be used in support of the war effort during WWII. He was isntrumental in many computing firsts, working with ENIAC, the Manchester Baby, supporting Maurice Wilkes in development of the EDSAC and then LEO.

In respect of LEO, Hartree's Wikipedia entry says: "Hartree's fourth and final major contribution to British computing started in early 1947 when the catering firm of J. Lyons & Co. in London heard of the ENIAC and sent a small team in the summer of that year to study what was happening in the USA, because they felt that these new computers might be of assistance in the huge amount of administrative and accounting work which the firm had to do. The team met with Col. Herman Goldstine at the Institute for Advanced Study in Princeton who wrote to Hartree telling him of their search. As soon as he received this letter, Hartree wrote and invited representatives of Lyons to come to Cambridge for a meeting with him and Wilkes. This led to the development of a commercial version of EDSAC developed by Lyons, called LEO, the first computer used for commercial business applications. After Hartree's death, the headquarters of LEO Computers was renamed Hartree House. This illustrates the extent to which Lyons felt that Hartree had contributed to their new venture.” 

His profile was published in the Oxford Dictionary of National Biography (ODNB), online and in print September 2004, written by C.G. Darwin and revised by Jon Agar.