Liberal Democrat
May 2, 1985 to May 4, 1989
May 6, 1993 to May 1, 1997
May 1, 1997 to June 7, 2001
June 7, 2001 to May 5, 2005
May 5, 2005 to June 4, 2009
June 4, 2009 to May 2, 2013
May 2, 2013 to May 4, 2017
May 4, 2017 to May 6, 2021
May 7, 2021 to Present
May 4, 1989 to May 6, 1993