Crompton and Company Limited originates in 1878 when Rookes Evelyn Bell Crompton took over the premises of T. H. P. Dennis in Chelmsford to form Crompton and Co, which soon became the country's leading distributor and manufacturer of electricity generating and lighting systems. In 1890 the chemist Joseph Swan sought his opinion when he first developed incandescent lamps for indoor use. Crompton immediately saw the potential and, within a couple of years, his firm was selling Swan's lamps and the generating equipment to go with them. Crompton and Co became involved in public lighting schemes, particularly railway stations, goods yards and the Alexandra Palace entertainment complex in north London. Here, he carried out many experiments on the effect of arc lighting on vegetation and flowers. Crompton afterwards reported that a young engineering student was often there, observing him at work. Crompton later discovered this student was Sebastian Ziani de Ferranti and that his visits had been the beginnings of his interest in electricity. The success of Crompton's British projects, led to a number of commissions in mainland Europe between 1885 and 1889. One such project was the Viennese Opera House, the first large theatre to be lit electrically anywhere. The public were astounded by the novel lighting effects that electricity could produce. Crompton was a shrewd businessman and went on to manufacture a.c. generators as well as the d.c. ones he had made his name with. He also helped extend the use of electricity into other areas - Crompton and Co invented the first electric toaster and some of the first electric ovens. In 1927, there was a merger between Crompton and Co and F. and A. Parkinson, a private company, which would be effected by Crompton purchasing the issued share capital of Parkinson; Armstrong Siddeley Development Co disposed of the greater part of its shares in Crompton. The move surprised the electrical industry although Crompton had not been especially profitable for some years. The new company was called Crompton Parkinson, with Frank Parkinson as chairman. By 1967, the Crompton name disappeared for a while from British industry when Hawker Siddeley took it over in 1967 but continued to live on in companies in Australia and India.

Crompton Parkinson Limited were Electrical engineers and manufacturers of a wide range of electrical components. They formed in 1927, by the merger of Crompton and Co (a lamp manufacturer founded by R.E.B. Crompton in 1878) and F. and A. Parkinson (a successful electric motor manufacturing company founded by two brothers, Albert and Frank Parkinson). In 1968, Crompton Parkinson was taken over by the Hawker Siddeley aerospace group. The Crompton range continued to be further diversified to incorporate cable, fuses, batteries and metering instruments in addition to lamps and luminaires. In 1970, after Hawkers took over Brook Motors, the 2 companies later became Brook Crompton Parkinson Motors.