He passed away at his Belgravia home after a four-month illness, which culminated in a stroke.
He is best remembered as having been in charge at Crawfords when, as part of DGC Holdings, which also included Dorlands, it was acquired by Saatchi and Saatchi in what was the biggest takeover in UK advertising history at the time.
Duncan’s son, Grant, followed his father into advertising, becoming chief executive at Publicis. He is now a senior executive at the headhunting firm, Spencer Stuart.
Born in a fishing village in north-east Scotland, Duncan studied art at Dundee College before responding to a newspaper ad for an art director at an agency in Singapore. He sent his portfolio and several weeks later received a job offer and a plane ticket.
It was during a seven-year stint in Singapore that he met his wife, Pat and where Grant was born in 1958.
Returning to London in 1960 he worked briefly for ABC Television before helping set up Colman Prentice & Varley’s Caribbean and Latin American network on the back of the agency’s international Shell win.
In 1967 he was hired by Norman Craig & Kummel as its UK managing director before becoming part of the NCK team poached by Eric Garrott to re-ignite his recent acquisition, WS Crawford.
The agency had suffered badly because of John Bentley’s asset stripping which had led to many clients leaving.
But by the 70s the agency had regained a top 50 ranking working with clients that included the AA, Max Factor, Duracell, Courtaulds and Vidal Sassoon.
In 1983 Saatchis merged Crawfords with Edinburgh’s Hall Advertising with Duncan becoming group chairman.
Duncan stayed with the group until1986 when Saatchis launched a third major grouping combining KMP, Humphreys Bull & Barker and Crawford Hall under the KHBB banner. Despite being offered the chairmanship, Duncan chose to quit.
He went on to buy into the communications group Burgess Daring which was acquired in 1988 by Osprey Communications.
In 1993 he engineered a management buyout of Osprey’s integrated communications subsidiary to create CIBGroup which he ran, retiring in 1998.
In 2005, Duncan told Campaign: "The industry has changed a lot since I worked in it – in terms of size more than anything. You see these agencies being sold for millions of pounds these days. Those kinds of numbers just don’t make any sense to me."
His funeral will take place on Monday 4 August at 4pm at Mortake Crematorium. Anybody who knew him is welcome to attend.