This is in line with an unspoken law that says the publication of anything able to embarrass former Labor ministers is in the public interest.

The decision to hold an inquiry and to provide it with the papers of the last government (in fact the antepenultimate government) is in breach of a well-known and recognised convention about new governments not having access to the papers of the previous administration. Tony Abbott has pushed forward against bureaucratic advice. At least some of that would have been disinterested, if only because of the precedent it would set.

Heavens, were there a pattern of such inquiries whenever there were new leaseholders at The Lodge we might have inquiries about why we went into Afghanistan, so disastrously and unprofitably and with so much useless effusion of blood, some of it our own. Or into Iraq. Or Vietnam, for that matter. Or into what ministers actually did know, or should have known about the wheat-for-oil scandal - the question John Howard would not allow his own limited inquiry to ask. Or what Howard and his office knew of the falsity of claims about children being thrown overboard in 2001.

There could be close - I should think minute-by-minute - scrutiny of the generalship (admiralship?) of Angus Campbell as he skilfully manoeuvred his fleet around the Indian Ocean and managed supplies of capsicum spray for use on recalcitrant civilians.

We might learn in our lifetimes every detail of the interactions between Scott Morrison and his colleagues, and his department and Fortress Australia during the refugee invasion. Not to mention about the management of our overseas concentration camps.

All of the documentation about dubious claims for travel and other expenses for attendance at the weddings of colleagues or shock jocks, ''charity'' functions and bike rides, bookshops and cabinetmakers could emerge. And how ministerial staff are chosen, and their conduct and conflicts of interest monitored.

I am very interested in such material. I could prolong my career drawing attention, much closer to events, to discrepancies between what was said then and what the record now shows.

My interest is not partisan. Julia Gillard and Kevin Rudd before her were habitual prevaricators and purveyors of half-truths, not to mention vague or weasel-worded denials. They used cabinet secrecy, or claims that documents were prepared for cabinet, to withhold information about any number of decisions we ought to know about. Some of my interest will extend to guilty knowledge about Craig Thomson, and the role of NSW ALP figures, some still in politics, in sustaining him.

Howard and Peter Costello hid behind cabinet confidentiality, and so, before them did Paul Keating and Bob Hawke. In the very first FOI case to go to the High Court, representatives of a Labor government had argued that I should not have access to documents said to have been created for Fraser cabinet purposes in 1982.

Tony Abbott said on Friday that departure from convention was justified because people died from mismanagement of the scheme. It wouldn't of course, be the first deaths said to be attributable to a cabinet decision, but in many cases the connection would be clearer. On roof insulation, there have been any number of inquiries, state and federal. None have shown any evidence of direct political culpability. At the height of the affair, Abbott suggested that politicians, from Rudd down, were guilty of industrial manslaughter. I doubt Ian Hanger, QC, will be asking about this.

In any event, it is clear that the new principles will be a bonanza for journalists, and possibly a tad embarrassing for politicians. We should not shrink on that account , and it is entirely typical of the courage of Brandis and his commitment to liberal values of freedom of speech and transparency of government that he does not.

Some poltroons will say the ''breach'' of convention will be the end of civilised and orderly government as we know it, but I am sanguine about that slight risk. Here in Australia, we hold back most cabinet documents for 30 years, although we are moving, by stages, towards 20. I can think of a few disclosures from the archives that have caused comment, embarrassment and debate, but I cannot think of any that have impacted on current politics. I do not expect that even more accelerated release would make a great deal of difference.

A US administration lasts no more than eight years. Most presidential documents, even national security ones, are in the public domain well within 10 - not a few long before that given the tendency of military, political and ministerial staff to write memoirs. They are helped by public spirited types such as Julian Assange and Edward Snowden. Would that Australia could produce such types!

But the best part is that the insultation documents are to go to Ian Hanger as royal commissioner. He's reliable for his discretion in such matters, as a quick glance at Carruthers v Connolly and others in the Supreme Court of Queensland will demonstrate.

A retired NSW judge, Ken Carruthers (who was judge in the Eastman trial) was asked to inquire into alleged political misconduct or corruption in Queensland. It had been revealed that there had been a secret deal between the short-lived National Party premier Russell Cooper and the Queensland Police Union, by which Cooper had promised the union the repeal of unpopular Goss government measures, the power of veto over senior police appointments, and increased police funding in return for a donation of $20,000 to party funds.

That inquiry dragged on (don't they all?) Meanwhile, Cooper received legal advice from a former Queensland judge, Peter Connolly, that the Carruthers inquiry was misconceived, and that persistence with the inquiry would be a waste of time.

Cooper decided on a further inquiry to inquire into the Carruthers inquiry. In search of a fair-minded inquisitor, his eye fell naturally on Peter Connolly, his own adviser. Connolly appointed Ian Hanger, as counsel to assist him. Hanger sent a peremptory letter to Carruthers warning him not to destroy documents

To describe Connolly as a judge of political inclination would be an understatement. Indeed, the Supreme Court judgment (by one of his former colleagues) includes evidence of a remark by him to a Criminal Justice commissioner that, ''Now that our side of politics is back in power, we can do a critique of the Fitzgerald experiment.''

The Connolly line of attack on the Carruthers' inquiry seemed to be that the Crime and Misconduct Commission was a Soviet or Gestapo-era kangaroo court whose officers, including judges, received and obeyed orders from ALP headquarters.

Alas the Queensland Supreme Court thought Connolly (and in consequence the employment of Hanger) a bit too much. It shut the Connolly inquiry down. Perhaps Hanger's new appointment can make amends for the lost income or opportunities.