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of Leeds, Yorkshire, and Arc Works, Chelmsford
Electrical engineers and manufacturers of a wide range of electrical components
1928 Some shares, all of which had been held privately, were made available for public ownership.
1930 E. J. Fox, managing director of Stanton Ironworks Co, elected to the board.
1932 Acquired Derby Cables and British Electric Transformer Co Ltd which was merged with the company's own transformer interests. Involvement in British Electric Transformer Co also gave the company control of Kye Lamps of Edmonton (reinforcing the company's interest in lamps) and Tricity cookers.
Manufacturing subsidiaries were established at Bombay and Sydney, with some high-profile power engineering, such as the electrification of the ice-plant at Fleetwood in 1932.
From 1932 the lamp business developed with the marketing of the ‘one-shilling lamp’.
1935 Successfully challenged the ‘Lamp Ring’ (the Electric Lamp Manufacturers Association), the manufacturing cartel established in 1919.
1935 Extension of new Arc Works
1937 Gained membership of the Electric Lamp Manufacturers Association.
1937 Manufacturing electrical engineers. "All-Test" Instruments. "Klosd" Motors. "Tong Test" Instruments. 
1938 Explored possible merger with Callender Cable in 1938.
1938 A new Guiseley factory was opened.
1939 The company commenced manufacturing .303 rifle ammunition at its Guiseley and Doncaster factories.
1941 Munitions produced at Chelmsford. Around 2,500 employed.
By 1946, Crompton Parkinson had established a leading position in battery-powered urban vehicles (in a joint venture with Austin) and its motors were used in trams, trolleybuses and diesel–electric locomotives.
1947 Acquired Cooke and Ferguson
1949 Advert: Young Batteries.
1952 Millionth electrical instrument
1956 Atomic Power Constructions Ltd was established to tender for nuclear power plant contracts; jointly owned by Richardsons, Westgarth and Co, International Combustion (Holdings) Ltd and Crompton Parkinson Ltd.
1957 New switchgear department.
1961 Manufacturers of induction motors; alternators; auto-synchronous motors; D. C. motors; D. C. generators; electric traction equipment; fractional H.P. motors; geared motor units; motor control gears; ceiling fans; power transformers; instrumental transformers; switchgear cars H. V. and L. V.; switchboard and instruments; portable instruments; paper cables; rubber cables; lamps; fluorescent tubular lamps; lighting fittings; street lighting equipment; electric vehicles; industrial trucks; batteries; stud welding equipment and fabricated steel tanks. 
1962 Pivotless instrument produced
1963 Motor Show exhibitor. Batteries
1966 Crompton Instruments moved to Witham
1968 Contract for lighting the new twin cargo terminals at Heathrow.
1968 Crompton Parkinson was taken over by the Hawker Siddeley aerospace group in 1968. The Crompton range continued to be further diversified to incorporate cable, fuses, batteries and metering instruments in addition to lamps and luminaires.
1995 Following a period under the control of the BTR group in the early 1990's, Crompton Lighting was subject to a management buy-out