David Caminer: System designer behind LEO, the world's first business computer

In 1947 J. Lyons & Co, the catering firm best known for its chain of teashops, made the extraordinary decision to build a computer. The Lyons computer, called LEO for Lyons Electronic Office, was the world's first computer designed exclusively for business. David Caminer, who had joined Lyons as a management trainee before the Second World War, was made responsible for the deployment of the computer in the Lyons business. In 1953, Lyons was the first company with a computerised payroll, and LEO soon took over the accounting and stock control of the company's 180 teashops. LEO gave Britain a world lead in business computers, albeit short-lived.

He was born David Treisman in 1915, the son of Henry Jack Treisman, a tailor in the East End of London, and his wife Rachel, a milliner. After David's father was killed in the trenches in 1918, his mother married Felix Caminer, and the young boy took his stepfather's name. David Caminer attended Sloane School, in Chelsea, where he was a keen rugby and cricket player. Growing up in the 1930s depression turned his political outlook towards left-wing causes. To the consternation of his parents he decided that a university education was an irrelevance in the economic gloom.

But he still needed a job and, fortunately, his next-door neighbour worked for Lyons and secured an interview for him. He was seen by J.R.M. Simmons who offered him a position in the Systems Research Office, which Caminer joined in 1936. Simmons was a leading light in the O&M (Organisation and Methods) movement, which sought to improve and mechanise office work. Lyons had a particular interest in office efficiency, because the wafer-thin profit margins of its teashops depended on the low-cost processing of thousands of tiny transactions every day.

On the outbreak of the war, Caminer served in the infantry with the Green Howards. He was wounded in action in Tunisia in 1943, losing his right leg as a result, and was invalided out. This must have been a terrible blow, because he had been an active sportsman. He returned to Lyons in 1944 and was made head of Systems Research.

In 1947 a Lyons fact-finding team visited the United States to catch up on new developments in office methods. They learned for the first time about the newly invented electronic computer. No machine had yet been built, but they learned that Maurice Wilkes at Cambridge University was as far ahead as anyone in constructing a machine. On its return to England, the team made contact with Wilkes, who agreed to supply the design information to Lyons, and Lyons agreed to provide some additional finance and manpower to the project.

The Cambridge machine sprang into life in May 1949, and Lyons then proceeded to construct a copy of the machine. A Cambridge engineer, John Pinkerton, led on the hardware side, while Caminer was put in charge of application development.

As today, many early computer projects went disastrously wrong. Not so at Lyons. Although the technology was radical and innovative, Caminer's approach to the computerisation of business processes was utterly conservative. He assumed that what could go wrong would go wrong. He therefore set out on a learning curve – computerising simple jobs first, and gradually taking on ones that were critical to the business, such as payroll and stock control. Caminer was an early advocate of management by exception, using the computer to bring critical issues to the attention of management.

By 1955 LEO was fully utilised, with Lyons own work and also that of other firms such as Ford and Kodak. Several companies expressed an interest in purchasing a copy of the machine, and this persuaded Lyons to go into the computer-manufacturing business as Leo Computers Limited. Caminer was appointed head of marketing in the new company and was eventually given a seat on the board. He was instrumental in supplying LEO computers for many important projects. These included the Post Office's telephone billing system and Giro, which were for several years the largest computer operations in Europe.

By the late 1950s, however, the American computer giants such as IBM and Univac had entered the British market, and it was clear that Leo Computers did not have the resources to compete in the long term. The firm was sold to English Electric Computers in 1963, and in 1967 English Electric's computer division was itself merged into ICL – the Wilson government's attempt to create a flagship national computer company that could compete with the Americans.

Caminer, and most of his colleagues in Leo Computers, were side-lined somewhat in the merger process. None the less, Caminer found a role as a senior marketer and advisor on large-scale computer applications. His most prominent achievement, in 1980, was implementing the computer and communications infrastructure for the European Economic Community in Luxembourg. This work was recognised with his appointment as OBE for services to the computer industry. He retired shortly after.

In retirement, Caminer remained committed to left-wing causes and was active in the Richmond Labour Party and the anti-apartheid movement. He remained deeply interested in the problems of implementing large successful computer systems. Though aware that each generation has to make its own mistakes, he was convinced that there was much to learn from the early developments at Lyons. He wrote articles and edited a book on applications development for LEO, and was a founder of the LEO Computer Society.

Martin Campbell-Kelly

David Treisman (David Tresman Caminer), computer applications designer: born London 26 June 1915; OBE 1980; married 1945 Jackie Lewis (one son, two daughters); died London 19 June 2008.