 In July 2017 Public Health England had bought the vacant site from GSK (GlaxoSmithKline) hoping to move altogether 2,745 jobs there, of which about 500 are from Porton Down.Nortel had a large site on the eastern edge of the town, acquired when STC was bought in 1991, and it was here that Charles K. Kao developed optical fibre data transmission.Nortel still has a presence, but it is much reduced.