Magna Carta in Australia has a habit of bobbing up right at the instant we're most particularly trying to pretend it doesn't exist, and this week has been a rather spectacular example, writes Annabel Crabb.

For an eight-centuries-old piece of hammered-out sheepskin, Magna Carta certainly has quite the black sense of humour.

Like Banquo's ghost, Magna Carta in Australia has a habit of bobbing up right at the instant we're most particularly trying to pretend it doesn't exist, and this week has been a rather spectacular example.

The story of how we came to have a rare copy of this grand document in our own bush capital is - like the evolution of the sentiments within the thing itself - a marvellous and intricate adventure that does not always reflect well on our species.

Our copy of Magna Carta - one of only four from the definitive 1297 version authorised by Edward I (under pressure, again, of widespread baronial mutiny) was found in a school desk drawer in England's West Country, among a heap of other old clutter, by senior history master Tom Tremlett in 1935. The school - Kings School Bruton - had no idea how it got there, but hung on to the treasure until 1951, when hard times arrived and the headmistress took it to the British Museum, where she was smartly offered £2500 for it.

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Well. The school knew (having also shrewdly consulted Sothebys) that it was worth more than that. Americans with silly money were rumoured to be prepared to pay much more. But Australia's prime minister and Anglophile-in-chief, Robert Menzies, got wind of the document's availability and made a spirited bid, securing the thing for £12,500 to the outrage a) of the British establishment that couldn't believe you would send a founding document straight to the convicts; and b) of the Australian population that couldn't believe you would pay that kind of money for a bit of manky old sheep hide.

Here's the magical part, though, as related most recently by former NSW chief justice and current ABC Board chairman, Jim Spigelman, in his fascinating paper, Magna Carta In Its Medieval Context (and yes, I would still think it fascinating even if he weren't my boss, thank you for asking). No one ever knew, exactly, how the Kings school had come by the Magna Carta. But when the scholar Nicholas Vincent (a renowned expert in all things MC) later went snuffling through some old deeds in the British Museum, he found a copy of the 1297 Forest Charter - a companion copy to "our" Magna Carta that was written and formalised at the same time - that had been donated in 1905 by a firm of London solicitors.

That firm, it turns out, had also represented the Kings School. Writes Spigelman:

Professor Vincent concludes that this Charter was only available for sale because of a clerical error made in the firm of solicitors. They had put the Magna Carta in the wrong envelope and sent it to the school, rather than include it, as he inferred the previous owner intended, in the 1905 bequest of both Charters to the British Museum.

Extraordinary. The wrong envelope. Such are the infinitesimal misadventures upon which even great events are sometimes built. Not to mention a corpulent paper profit for the Commonwealth of Australia, whose bold investment in 1952 is worth, today, in all likelihood somewhere north of $20 million.

(The Wikipedia entry for the Kings School today, meanwhile, notes two major points of interest from the school's 500 years of existence: that England Rugby coach Brian Ashton was formerly a history teacher and sports coach there, and that the school once owned a 1297 copy of Magna Carta, which it sold to Australia for a song).

Nothing that physically happened to this little closely-written 43cm by 47cm scrap, however - no chance human idiocy or miracle of fate, nor calculated act of political opportunism - could be more remarkable than the contortions performed by governments who purport to honour Magna Carta while simultaneously exempting themselves from its purest principle.

Let us remember that Magna Carta - a deal initially hammered out between some pissed-off barons and the serially unreasonable King John in 1215 - established a lot of principles over its initial and subsequent versions. Like the ideal width of a piece of cloth, protection against mandatory imprisonment, and some seriously radical thinking about scutage, which sounds like something to do with sanitation but that actually means, more or less, taxation. Lots of Magna Carta's elements have lapsed, but if there is an immortal, surviving principle of the document, it is that the state is not above the law. That the law of the land applies even to those who make it, or who seek to enforce it - even kings. (This may be an unremarkable principle today, but it was pretty wild in 1215).

When Magna Carta finally fluttered - on the butterfly wing-gust of the above-outlined random events - across the changing globe to Canberra, it was welcomed warmly by Menzies, who observed that "the great significance of the great charter is that it was the first charter (in) which we have record of what we now call civil rights or civil liberties".

The year was 1952. Prime minister Menzies' zeal to obtain a copy of Magna Carta, and his love for its principles, somehow co-existed with the other stuff he was doing at the time, like giving his executive extraordinary powers to shut down organisations they judged to be associated with the Communist Party.

When Menzies finally got the Communist Party Dissolution Bill through the Parliament in 1950, it was subjected immediately to a High Court challenge, which overturned the legislation and produced some of the most memorable legal rhetoric in Australian history.

Much of it very precisely about the principle that governments should not consider themselves above the law, or rearrange their powers to suit themselves.

"The stream cannot rise above its source," admonished Justice Fullagar, in one of those lovely moments where a jurist - stripping away the fibrous caveats that so often encase legal opinion - comes up with a perfectly simple, crystalline expression of a legal concept that anyone could remember and whistle.

He also nicely summarised the separation of powers, which gives Parliament the job of making laws, and the courts the job of deciding whether they've been broken in any particular instance; this was a big problem with the Communist Party legislation, which allowed the Government enormous latitude in deciding who was a Commie and who wasn't.

"A power to make laws with respect to lighthouses does not authorise the making of a law with respect to anything which is, in the opinion of the law-maker, a lighthouse," concluded Fullagar J, who really was on rhetorical fire in that judgment.

In September 1951, a frustrated Menzies took the matter to a referendum - and lost, opposed by a Labor Party whose fear of electoral opprobrium and being called Commies was eventually trumped on this occasion by conviction on the principle. Labor's campaign paraphernalia declared the party to be "for Magna Carta, and the rule of law".

Less than a year later, Magna Carta itself arrived in Canberra, to welcoming speeches from everybody. Honestly, you wouldn't read about it.

So - back to the present.

On this Sunday just gone, another Anglophile Prime Minister went to Magna Carta Place - a reassuringly pointless little domed folly just west of Old Parliament House - to celebrate the great charter's 800th birthday. Prime Minister Tony Abbott enthused:

It's really good to be here at the Magna Carta monument in Canberra to begin what will be some weeks of commemoration of Magna Carta. It was signed 800 years ago and 12,000 miles away, yet it remains a very important foundation stone of our democracy, it remains a very important watershed for the whole world, because decency, civilisation, human rights utterly depend upon the rule of law; the acknowledgement that no one is above the law, not even the King, which was first given expression all those years ago and all that distance away at Runnymede in 1215. It's very fitting that this Magna Carta Place should be within a hop, skip and a jump of our own national Parliament.

These boilerplate formalities out of the way, the PM was then asked a number of questions by attending journalists.

He was asked if it was indeed true that agents of the Australian Government had paid money to criminal people-smuggling syndicates to have them take asylum seekers back to Indonesia.

"There's really only one thing to say here and that is that we have stopped the boats," he replied.

The Prime Minister was then asked about his plans to have ministers decide, rather than courts, whether terrorist suspects were sufficiently guilty to warrant the stripping of their Australian citizenship.

("Why should this power be exercised by a minister and not the courts?" asks a prompt sheet for Coalition MPs leaked this week to the West Australian, before answering itself, with Orwellian verve: "A law requiring a terrorist conviction would be toothless.")

The Prime Minister's answer: "This is all about saying if you're a terrorist and you go off and fight for a terrorist army that wants to do damage to Australia, that wants to do damage to Australian service personnel, if you're in that position and you're a dual citizen, you can't expect to come back to this country."

The death of satire has been declared a few times, most memorably when Henry Kissinger won the Nobel Prize for Peace. And I've felt like checking its pulse this week at a number of points; Bronwyn Bishop encouraging a statutory officer to be impartial, the Indonesians accusing Australia of bribery, and so on.

But for rhetorical and comic ambition, to begin a doorstop with lavish praise of Magna Carta and then end it by explaining on not one but two fronts how it's really better for everyone if you ignore its central, shining principle - that's hard to beat.

Happy birthday, great charter. Long may you live to embarrass us at key legislative moments.

Annabel Crabb is the ABC's chief online political writer. She tweets at @annabelcrabb.