Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 132,615 pages of information and 209,984 images on early companies, their products and the people who designed and built them.
of St. Albans.
1936 Private company.
1946 The holding of Cable and Wireless in Marconi's Wireless Telegraph Co was acquired by English Electric Co. As well as the whole of the share capital in Marconi's Wireless Telegraph Co, this also gave English Electric the entirety of Marconi Instruments Ltd.
1958 Marconi Instruments Ltd offered more than 100 different instruments and was developing in nuclear power instrumentation, guided weapons testing and multi-channel radio link equipment.
1961 Manufacturers and designers of telecommunication measurement equipment, industrial electronic instruments, industrial X-Ray apparatus, diagnostic and therapeutic X-Ray apparatus and electro-medical equipment. 1,500 employees. 
1974 Developed a spectrum analyser MI TF2370.