The representatives of both wings of the political class – Nick Minchin and Peter Beattie – looked like going into meltdown as Christine Milne and Bob Katter, for somewhat different reasons, denounced the free trade and deregulatory neo-liberal consensus that has dominated our politics for decades.

Minchin came as close as I’ve ever seen him to passion: on the topic of not having tariffs.

(It was also interesting to watch his finger tapping as Bob Katter denounced the Coalition’s record on agriculture. And it was choice to see Katter set Minchin a reading list of De Tocqueville and Mill.)

Minchin’s argument of last resort was to invoke cheap food.

To return to my early 20th century British politics parallels, the Liberal party came to power in 1906, after much agitation for agricultural tariffs from within the Tory party, on a cry of “cheap bread”. At the same time, of course, that line resonated because wages were stagnant or falling, employment insecure, and the legal rights of trade unions under attack.

It’s always worth asking precisely why cheap food is such a pressing concern.