Rowling, who has been at the center of a rancorous online debate about transgender rights in recent weeks, put her name to the letter, which said: "The free exchange of information and ideas, the lifeblood of a liberal society, is daily becoming more constricted."

It added: "We uphold the value of robust and even caustic counter-speech from all quarters. But it is now all too common to hear calls for swift and severe retribution in response to perceived transgressions of speech and thought."

The missive, titled "A Letter on Justice and Open Debate," said that this creeping cancel culture will harm the most "vital causes of our time" by silencing "good-faith" disagreement.