Marshall Cavendish chief executive Hooi Kee Sum has resigned suddenly after more than seven years at the part-work publishers.
Sum is still serving his notice and a Marshall Cavendish spokesman would not give a reason for the his departure.
He has headed the UK subsidiary of the Singapore-based Times Publishing since April 1992, taking the helm from Lim Chin Geok who left for health reasons.
Marshall Cavendish publishes a number of titles including Get Crafty, Great Composers and DIY Profile. It recently moved into the interactive market, putting its Images of War title on CD-Rom.
Times Publishing, quoted on the Singapore stock exchange, had in the year to August 1995 consolidated sales of 225m and pre-tax profits of 14.4m.
Marshall Cavendish has a UK advertising budget of about 5m, according to Register-MEAL.
In July the publisher awarded its media account to the newly formed agency New PHD in a pitch against the Media Business, the Media Centre and the incumbent John Ayling & Associates.