First appointed Director-General
October 1925 to October 1933
October 1933 to August 1949
Director, 1933-1934
Director, 1934-1949
September 1949 to June 1956
July 1956 to April 1964
May 1964 to August 1965
September 1965 to January 1983
January 1983 to May 2000
May 2000 to May 2004
May 2004 to January 2006
January 2006 to May 2008
May 2008 to July 2012
September 2012 to May 2016
May 2016 to July 2018
July 2018 to January 2019
Chairman, 1965-1979
Chairman and Convener, 1980-1991
Convener, 1991-1997
Chairman, 1998-2000
Chairman and Convener, 2000-2008
Member and Convener, 2008-2016