It is believed Gary Digby, the sales director, will take on Duff's responsibilities until a full-time replacement is hired.
Duff, a former chief executive of Granada Enterprises, became ITV Sales' managing director in November 2003 after a face-off for the top job against Martin Bowley, his counterpart at Carlton TV. Duff had joined Granada from Zenith Media in 2001 to replace Mick Desmond, who took on the new role of joint managing director of ITV.
Following his appointment to the top ITV Sales job, Duff was responsible for integrating the Carlton and Granada sales departments into one unit, which resulted in the loss of nearly 300 jobs, and for hiring the rest of the company's executive board.
He then re-engineered the ITV sales function, ridding the organisation of many of its old guard and putting greater focus on customers. Duff was responsible for hiring Justin Sampson, then the Radio Advertising Bureau's managing director, to lead a customer relationship department.
Duff was also a key player in the creation of Thinkbox, the commercial TV industry marketing body, and is a member of its executive committee.
Duff was not available for comment.
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