London City brand was created in 1969 by the Dutch Sound Experience (DSE) to produce a cheaper alternative to Marshall amplifiers. By the early 1970s London City amps had a characteristic turquoise blue color. The brand lasted until the early 1980s. London City has since been revived as a guitar and amplifier company

Source: Dr Tube - London City Schematics (16 January 2018)

Source: London City guitars and amplifiers website (16 January 2018)