Reverse ferret is a phrase used predominantly within the British media to describe a sudden reversal in an organisation's editorial line on a certain issue. Generally, this will involve no acknowledgement of the previous position.
The term originates from Kelvin MacKenzie's time at The Sun. His preferred description of the role of journalists when it came to public figures was to "stick a ferret up their trousers". This meant making their lives uncomfortable, and was based on the supposed northern stunt of ferret legging (where contestants compete to show who can endure a live ferret within their sealed trousers the longest). However, when it became clear that the tide of public opinion had turned against the paper's line, MacKenzie would burst from his office shouting "Reverse Ferret!"
In 2014, the Mayor of New York performed a literal reverse ferret when he repealed a ban on owning domesticated ferrets within the city.
Republican leaders' reaffirmation of support for 2016 presidential nominee Donald Trump in October was described as a reverse ferret by The New York Times.