From Graces Guide
of 3 Albemarle Street, Clerkenwell, EC1 (1937)
1924 Private company.
1937 Gun mountings, ground equipment, searchlight mountings. "Opperman" Reduction Worm Gears. 
WWII Manufactured parts for the De Havilland Mosquito.
1961 Manufacture a wide range of spur, worm and helical gear units embodying any make or type of electric motor. 
1968 Because of broadening range of business the company name was changed to Opperman Holdings
Sources of Information
- 1937 The Aeroplane Directory of the Aviation and Allied Industries
- 1961 Dun and Bradstreet KBE
- The Times, Jun 01, 1965
- The Times, Apr 16, 1968
- The Times, Sep 01, 1973
- Mosquito by C. Martin Sharp and Michael J. F. Bowyer. Published by Crecy Books in 1995. ISBN 0-947554-41-6