Standard Telecommunication Laboratories was the UK research centre for Standard Telephones and Cables (STC). Initially based in Enfield, North London, and moved to Harlow Essex in 1959. At this time STC was part of ITT.
It is now recognised as the birthplace of optical fibre communications, for it is here that Sir Charles K. Kao, George Hockham and others pioneered the use of single-mode optical fibre made from low loss glass. In 2009 Charles Kao was awarded the 2009 Nobel Prize in Physics, for pioneering optical fibre communication.
Another famous name associated with STL is Alec Reeves, previously famous for inventing pulse-code modulation while working at the Paris labs of the parent company ITT in 1938, and for his invention of the wartime bomber navigation system OBOE. Alec headed a team working on various means of optical communication, prior to the emergence of glass optical fibre as the leading contender.
Nortel subsequently encountered financial difficulties, and was broken up and sold off. The last remnants of the laboratories at the Harlow, Essex site, have now disappeared.