Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 147,372 pages of information and 233,518 images on early companies, their products and the people who designed and built them.
1989 ADT focused on electronic security systems and car auctions by disposing of its property maintenance and services activities
1996 Absorbed the Thorn Security business soon after EMI had been demerged from Thorn EMI, and all but a handful of the famous red 'THORN' bellboxes were replaced. However, the Fire products may still be found in many premises and until recently spares and complete systems of Thorn heritage continued to be manufactured by ADT.