The development of electronic computers in the late 1940s was largely carried out by mathematicians and engineers, who saw an opportunity to automate the operations of earlier electro-mechanical devices that had been built to solve equations or do complex calculations.

The Mark 1 at Manchester and Cambridge’s EDSAC (electronic delay storage automatic calculator) computer were used to calculate accurate mathematical tables or analyse data relating to protein structures, developing work done on ENIAC (electronic numerical integrator and computer), Colossus and other military systems. Some, however, anticipated the business applications of the new technologies, among them David Caminer, a key member of the management team that developed the first computer systems to automate common business processes at the caterers J. Lyons and Co.

The comptroller (financial controller) of Lyons, John Simmons, had realised as early as 1947 that the new generation of digital computers could be used in business, giving Caminer the opportunity to pioneer the application of business systems analysis to the specification and development of computer-based processes. The approach he introduced formed the basis of data-processing and commercial systems throughout the 1960s and 1970s, providing a foundation for today’s reliance on information and communications technologies in business and elsewhere.

Caminer was the son of a Jewish tailor working in the East End of London, and was born David Tresman. His father died shortly before his third birthday while on active service during the First World War, and he became David Tresman Caminer when his mother remarried.

He attended Sloane School in Fulham but was involved in left-wing politics and chose not to go to university. When he eventually decided that he needed a job his mother asked a neighbour who worked at Lyons if there was a place for her son, and Caminer joined as a management trainee in 1936 at the age of 21.

With its popular tea shops around the country and a chain of successful Corner Houses in Central London, Lyons was a large and rapidly growing catering business offering many opportunities for a talented and effective young manager.

During the Second World War Caminer served with the Green Howards, but in March 1943 he was injured at the Battle of Mareth in the Tunisian desert and lost a leg. He returned to Lyons in 1944, working for John Simmons, and soon became head of the systems research office, applying the new disciplines of organisation and methods to the company’s operations.

Senior managers at Lyons saw the importance of the application of numerical processing to the sort of routine data-processing that dominated the activities of a business that made and distributed tens of thousands of cakes and cups of tea every day. In 1947 they donated £2,500 towards the development of EDSAC by Maurice Wilkes and his team at Cambridge in return for access to the technology, and by 1949 a small electronics workshop had been set up at the head office in Hammersmith, West London.

Lyons decided to build a computer for itself, based on EDSAC but modified to meet its own needs, and Caminer was given responsibility for systems and programming development while his colleague John Pinkerton was responsible for the hardware side. The system was called LEO, the Lyons Electronic Office, and by 1951 it was running test programs and could be demonstrated to Princess Elizabeth when she visited the Lyons head office at Cadby Hall in Hammersmith.

The final system occupied more than 5,000 sq ft in 21 racks, using about 6,000 thermionic valves and was first used to cost the bread, cakes and pies produced at 12 Lyons bakeries. It ran successfully on November 17, 1951, and weekly thereafter, the first scheduled business computer system.

In December 1953 Caminer supervised the world’s first full-scale business computer program when LEO produced pay cheques for 1,670 bakery staff. The average time to work out one person’s wage was cut from about eight minutes to 1.5 seconds, a clear demonstration of the potential efficiency gains possible with even the earliest computers.

The success of the LEO prompted Lyons to spin off the computing side of the business as a separate company, Leo Computers. The company built a new and improved version of LEO, the LEO II, and in 1959 Caminer joined the board as head of marketing, although he still retained responsibility for systems implementation.

Growing pressure from US companies, including IBM, prompted consolidation in the fledgeling British computer industry during the 1960s, with Leo Computers merging with English Electric in 1963. The merged company acquired Marconi’s computing division in 1964 to form English Electric Leo Marconi Computers, later simplified to English Electric Computers and then, following a merger with ICT, to International Computers Ltd or ICL.

Caminer stayed with the company throughout these many changes, and was involved in the complex process of designing a unified range of mainframe computer systems for the merged organisation. His final big project was as project director for the development of a computer and communications network for the European Commission, and in 1980 he was appointed OBE for “services to British commercial interests in Luxembourg”.

He retired from ICL in 1980 but remained active in the industry as a consultant and writer. During his retirement he established a reputation as the foremost historian of the LEO computer, and in 1998 he published LEO: The Incredible Story of the World’s First Business Computer. He was given an honorary doctorate by Middlesex University in 2006 in recognition of his contribution to business computing.

Caminer married Jackie Lewis in 1945 and is survived by his wife, one son and two daughters.

David Caminer, OBE, business computing pioneer, was born on June 26, 1915. He died on June 19, 2008, aged 92