On the dotted line: King John signing Magna Carta at Runnymeade 15 June 1215. Photograph: Universal History Archive/Un/REX
It was on 15 June 1215 that King John, in the meadow of Runnymede beside the Thames between Windsor and Staines, sealed (not signed) the document now known as the Magna Carta.
Today, jets taking off from London Heathrow airport come up over Runnymede and then often turn to fly down its whole length before vanishing into the distance.
Yet it is not difficult to imagine the scene, during those tense days in June 1215, when Magna Carta was being negotiated, the great pavilion of the king, like a circus top, towering over the smaller tents of barons and knights stretching out across the meadow.
The Magna Carta is a document some 3,550 words long written in Latin, the English translation being “Great Charter”. Much of it, even in a modern translation, can seem remote and archaic.
It abounds in such terms as wainage, amercement, socage, novel disseisin, mort d’ancestor and distraint. Some of its chapters seem of minor importance: one calls for the removal of fish weirs from the Thames and Medway.
Yet there are also chapters which still have a very clear contemporary relevance. Chapters 12 and 14 prevented the king from levying taxation without the common consent of the kingdom.
Chapter 39 laid down that “No free man is to be arrested, or imprisoned, or diseised [dispossessed], or outlawed, or exiled, or in any way destroyed, nor will we go against him, nor will we send against him, save by the lawful judgement of his peers or by the law of the land.”
In chapter 40 the king declared that “To no one will we sell, to no one will we deny or delay, right or justice.”
In these ways, the Charter asserted a fundamental principle – the rule of law.
The king was beneath the law, the law the Charter itself was making. He could no longer treat his subjects in an arbitrary fashion.
It was for asserting this principle that the Charter was cherished by opponents of Charles I, and called in aid by the founding fathers of the United States. When on trial for his life in 1964, Nelson Mandela appealed to Magna Carta, alongside the Petition of Rights and the Bill of Rights, “documents which are held in veneration by democrats throughout the world”.
Chapters 39 and 40 are still on the statute book of the UK today.
The headline of a Guardian piece in 2007 opposing the 90-day detention period for suspected terrorists was “Protecting Magna Carta”.