Students at the University of Melbourne protest a visit by Tony Abbott in 2014 (Image: AAP/Julian Smith)

Last week Crikey added up the cost of the free-speech martyrdom of climate and reef science sceptic Peter Ridd.

Ridd's sacking by James Cook University has launched court actions, occupied valuable Senate committee airtime and been a cause celebre of the free market pressure group, the Institute of Public Affairs (IPA), which has a related taxpayer-subsidised charity arm.

It has also been on the agenda of a federal government inquiry -- established by Education Minister Dan Tehan -- into freedom of expression on campuses, with former Deakin University vice-chancellor professor emeritus Sally Walker appointed to review the workings of a new model code to be introduced by universities by the end of the year.