In light of amendments to Ireland's Defamation Act proposed by Irish Minister for Justice, Equality and Law Reform, Dermot Ahern, including changes which rendered the crime of blasphemous libel prosecutable for a fine of up to €100,000 (US$135,000).
In 1979, Duke was a founding member of the Gay Humanist Group, (now Gay and Lesbian Humanist Association) after Mary Whitehouse began a private prosecution for blasphemous libel against Gay News (see Whitehouse v Lemon.