In 1977 she led a prosecution for Blasphemous libel against Gay News and its editor, Denis Lemon for publishing a poem called The Love that Dares to Speak its Name by James Kirkup. Lemon was found guilty and received a suspended prison sentence. This case led to a campaign, for instance by the National Secular Society, for the abolition of the blasphemy laws. Whitehouse responded to this by declaring in public that "everything good and true" that "every decent person believes in" was being undermined by "the humanist gay lobby". This in turn led to some people deciding that there ought to be an organised humanist gay lobby and setting up the Gay Humanist Group, now GALHA.
In 1982 she attempted to prosecute Michael Bogdanov, the director of a National Theatre production of Howard Brenton's The Romans in Britain, the first act of which contains simulated male rape, but the prosecution was abandoned and Mrs Whitehouse had to pay the costs. In 1993 her biography was published .
- Quite Contrary by Mary Whitehouse (Sidgwick and Jackson:London 1993)