He pleaded guilty once he understood, he didn't have a legal leg to stand on!

Signing the official secrets act, means you keep thing you've seen, heard or know regarding nation security, or the official secrets act, to yourself! No if, buts or maybes!
Alan B.

"not that orders are relevant to the question of duty but rather that they trump anything else, so that you must obey". This was irrespective of "how unreasonable or in breach of fundamental principles of justice they may be, and will commit criminal offence if he does not".

The above would be fine if the senior/superior officer was of sound mind, sound competence & above all, sound mentality.
More often than not, nepotism/Peter Principal ensure that these qualities are rarely, if at all found in "superior" officers in the higher ranks of the Bureaucracy in all sectors of Govt !
Away from the battlefield the Armed Forces are more likely than not mere bureaucracy !
Whatever evidence is available to the public seems to suggest that. Standing behind politicians giving some explanation & nodding in agreement does not instil much confidence in such officers.

Multiple theories at work here for reconsideration:

1. The theory of the sinking ship viz:
Loose lips sink ships!

2. The Sergeant Schultz Theory viz:
Know nothing, see nothing and do nothing!

3. And as for this subject generally , the KISS theory viz;
Keep it simple stupid!

On reflection, one more theory should be added to the mix.

4. The theory of Karma viz.
What goes around comes around.

Squealers are unpleasant people methinks!

One only needs to look to the treatment of Julian Assange to witness Australia's (our "government's") attitude to whistleblowers. In a 2022 article, Gerry Georgatos of Social Justice Independent writes "Australia has a firmament of adversarial governances, and inculcating cultures of unaccountability." Further, he writes: "There are layers of preposterous extra-legal protections to ensure the veils of secrecy." Allan Kessing, who in 2003 wrote reports on airport security for Air Border Security (a now defunct organisation) was pilloried by none other than Herr Fuhrer Howard for: "allegedly passing on information" contained within the buried reports. The Howard years, per incumbency, saw the greatest volume of enacted laws and regulations passed restricting freedoms & civil liberties since the Whitlam prime ministership, many whose ramifications today echo loudly in contrast to whistleblower protection legislation. My own experiences with APS when attempting to elucidate security inadequacies at a facility in WA resulted in my contract being "terminated under probationary clauses"...that old chestnut ! Suffice it to say, when I bumped into former workmates from this facility some 4 years later, all of those security concerns I had raised had been rectified and implemented.

Squealers are unpleasant people methinks!
diver dan,
What would you call someone with the integrity & guts to make a stand against the immense odds such as incompetence & corruption in the Peter Principle ranks ?
In my book the squealers are those who lack the cajones to demand merit from those whom they kowtow to !