James Garrett, who founded the company in 1963, is retiring at the age of 75.
He said: "This seemed a good time to pull down the shutters on an immensely enjoyable working life."
In 1983, Garretts' "Manhattan" spot for BA marked a turning point for British Airways in reflecting its increasing corporate confidence. Directed by Richard Loncraine for Saatchi & Saatchi, the 90-second ad presaged the increasing influence of special effects in advertising.
Garretts also produced other notable campaigns, including the launch of After Eight for J. Walter Thompson, "moving oil" for Castrol for Bates Dorland, "pawnbroker" for Levi's through Bartle Bogle Hegarty, most of JWT's BT ads starring Maureen Lipman and Publicis' Renault Clio "Nicole-Papa" campaign.
Garretts' staff of about ten includes the producers Sue Hildrey, Gerald Berman and Hans Elias and the directors Richard Loncraine, Nigel Cole, Rod Butcher and Carl le Blonde. The Annex, launched in 1986, is a Garretts offshoot.