A Fund for Justice and Education has been established by the American Bar Association as part of the 800th anniversary celebrations of Magna Carta. Those who give between $10,000 and $24,999 have the honour of being members of the King John’s Circle. This may be a 21st century attempt at inclusiveness, but it seems baffling that anyone at a time like this would want to have their name associated with King John. The king only agreed to the Charter under duress, and quickly reneged, with the support of his New Best Friend and Feudal Overlord the Pope.

Part of the brilliance of this book by Anthony Arlidge QC and Lord Judge is that it reminds us that so much of what happened before and long after Runnymede was a function of the character of the men involved; men who acted from a distinct mixture of motives which we in our own time understand all too well. As for the heroes of the story, the Rebel Barons (after whom no ABA Circle of supporters is expressly named), they soon invited over a French prince to usurp the lawful English dynasty, an enterprise that only ended after John’s death and with final military defeat in a civil war.

Money is crucial to the story. Medieval kings were always in need of cash to fight wars and to maintain a kingly court. John understood that for him it was a better deal not to insist on his barons providing fighting men in fulfilment of their feudal duties, but instead to tax them and to hire more efficient mercenaries. Those who had the money wanted something for their own self-interest in return. Unfortunately for John, he got the men but lost the war: his defeat at the Battle of Bovines 11 months before Runnymede left him without money or authority and set in motion the events we commemorate this year. Magna Carta was as much about commercial rights as it was about trial of one’s peers, which the authors explain was not a precocious medieval guarantee of trial by jury as we now know it. Clause 39 “does not say how your peers will judge you nor what the law of the land is. It is this vagueness which has made it a perfect vehicle to support the arguments of later generations, seizing upon it as justification for their policies.” No one imagined that Clause 40 (“to no one will we sell, to no one deny or delay right or justice”) would be used nearly 800 years later as an argument against the Legal Aid, Sentencing and Punishment of Off enders Act 2012 (LASPO).

The Charter (not then called Magna) was reissued several times as part of the endless bargaining process between rebellious subjects and a king trying to get his own way. Several clauses were amalgamated or deleted in this process. After a period out of the limelight it figured importantly in the constitutional crises of the early 1600s. It became a precedent for the principles that the king was subject to the law, that the courts were not obliged to accept “reason of state” as a justification in itself for the use of prerogative power, for the independence of the judiciary and for the principle that the king had to act only with the consent of Parliament and not merely because he had consulted them.

All this is set out with clarity and scholarship in this book. The chapters are arranged chronologically and thematically, thus explaining what many of the clauses meant, e.g., what was and who was a “freeman” and what the position was in respect of taxes, trials and commerce. The story is then taken forward as far as the establishment of the American Bill of Rights and beyond, to when Magna Carta was cited as grounds for allowing Paula Jones to sue the serving President Clinton for sexual harassment.

In addition there is a comprehensive and useful Timeline, potted biographies of the rebel barons, a translation of Magna Carta, the Petition of Right, and the Bill of Rights, both British and American. Between them the authors have over a century of experience in studying authorities, turning disparate sources into a narrative and reconciling conflicting dicta and contradictory first-hand evidence. As Middle Templars, they pay due respect to the key role played by William Marshal, whose effigy remains in Temple Church. Those of us familiar with their public prose may identify who wrote which chapter but the prose is a joy in its own right. In 1636, the Assembly of the colony of Maryland declared that the inhabitants had all the rights and liberties “according to the great charter of England”. The authors continue, “Unsurprisingly, the legislation did not receive royal assent [from Charles I], not least because the King was advised by the Attorney-General that this might not be agreeable with the royal prerogative. The King might have thought that one out for himself.”

Those who want to know why this anniversary is so important need read no further.