The Plessey Company Plc was a British electronics, defence and telecommunications company that was formed in 1917 by various shareholders including a German born production engineer called William Oscar Heyes whose wife Elizabeth came from the Northumberland locality Plessey from which the company name is partly derived.
Through the 1920s and '30s the company expanded its work into the development in radio and by the outbreak of World War Two was in a good position not only to provide communication equipment for the armed forced as well as diversify into war production. At its peak the Plessey factory in Sunderland employed more than 3000, many of whom were women working in wiring, relay adjust, assembly and support functions. The factory closed in 1977 following cuts to telecommunications budget under Harold Wilson's Labour government the year previous. Trade unions on site didn't go down without a fight arranging a sit-in at the factory as well as sending a delegation to meet government officials in London.