In the days when university students were conspiring to stop the Vietnam War by holding flowers and singing, the Security Intelligence Service looked after the interests of the nation by sending agents on campus. Students could spot them without even checking their briefcases for pies and copies of Penthouse : the short sideburns and grey suits made them easy to tell apart from the young Nats.

These days the SIS sends letters instead of agents. A November 6 missive from director Warren Tucker encouraged universities to be aware of "illicit science and technology acquisition" which might be used to make weapons of mass destruction.

It's the wrong month for April Fool's Day jokes, so we assume it was meant seriously. Certainly university staff union spokesman Tom Ryan got very worked up about the threat the letter posed to the "legislated autonomy" of universities, including the guarantee of academic freedom.

It's hard to say which is more Alice-in-Wonderland: the idea that a terrorist might be cooking up a WMD in the biology lab or the notion that stopping him doing so might constitute an abridgement of his right to academic freedom.

Last time we looked, the universities' statutory role of being critic and conscience of society did not include knocking up a nuke in the lunch hour.

Most academics would probably say something if they saw a colleague backing a trailerload of weapons-grade plutonium up to the staffroom door. And chances are it wouldn't be "Oh, he's just exercising his statutory right to express himself ." But it's good to know that the SIS is making sure.