Sumlock ANITA calculator

The ANITA Mark VII and ANITA Mark VIII calculators were launched simultaneously in late 1961 as the world's first all-electronic desktop calculators. Designed and built by the Bell Punch Co. in Britain, and marketed through its Sumlock Comptometer division, they used vacuum tubes and cold-cathode switching tubes in their logic circuits and nixie tubes for their numerical displays.

They were the first of a series of desktop and hand-held electronic calculators that the company was to develop and sell under the ANITA name into the mid-1970s.

The acronym 'ANITA' was officially proclaimed to be derived from, variously, A New Inspiration To Arithmetic, or A New Inspiration To Accounting, though there have been rumours that this was also the name of the designer's wife.

The Bell Punch Company (named after its first product, a ticket punch with a bell used by tram and bus conductors) had been producing a very successful range of key-driven mechanical calculators of the Comptometer type under the names "Plus" and "Sumlock", since the 1930s. In 1956 the young graduate Norbert Kitz (also known as Norman Kitz), who had worked on the early British Pilot ACE computer project, had a chance meeting with some of the directors of Control Systems Ltd., of which the Bell Punch Company was then a subsidiary. Some years earlier, while researching the introduction to his dissertation, he was looking at the mechanical calculators in the Science Museum, London, United Kingdom, and had realised that the future of calculators lay in electronics. Unfortunately, the major mechanical calculator manufacturers were far away in the U.S. and Germany, and Kitz's idea lay dormant until he raised it at that meeting. The directors were very forward looking and were impressed by Kitz and his idea. They decided to open an Electronics Development Department, and took on Kitz as the leader of a project to develop an electronic version of the company's mechanical calculators. To help confidentiality the project was given the code-name ANITA.

...
Wikipedia