The sheer size of the American Bar Association annual meeting is what makes it so amazing. Even though the number of members visiting London this week is lower than expected, there will still be over 3,000 lawyers attending some 225 meetings and events. Each of the specialist sections could probably put on one of the Law Society's annual gatherings by itself – just imagine half-a-dozen or more plenary sessions running simultaneously and you can see why the ABA needs more than 80 hotels. I remember covering its last visit to the UK 15 years ago and I can tell you that the sight of all those lawyers surging up and down Park Lane was awesome.

Partly to see how it works from the inside I have agreed to introduce and "moderate" a session. During the morning there will be two mock trials and in the afternoon delegates will discuss the issues raised. The trials may be fictitious, but the chargeable hours that have gone into preparing them would be beyond the means of anyone below a small multinational corporation. The lawyers and judges are of the highest order – the first case to be heard by Lord Phillips since he became Master of the Rolls will be pure make-believe.

And when it comes to mock defendants, only the most famous will do. President George Washington will be prosecuted in London, accused of high treason. Mid-morning, the tables are to be turned, the king against whom Washington is accused of levying war will be sued in the Massachusetts courts over the events leading to the Boston Tea Party.

Mock newspaper articles offer a flavour of the event. The London Evening Post has "loathsome George Washington" charged with "levying war and exciting rebellion in our insubordinate colonies". We are told that if convicted he will be "drawn, hung, disembowelled, burned, beheaded and quartered". Offering a different perspective, the American Herald has the "father of our country violently kidnapped" for "heroically leading the American army, bravely defying King George's malicious decree and brilliantly consorting with the king's enemies to end the Crown's oppressive and tyrannical dominance of America."

The same US newspaper takes delight in the prospect that King George III will answer for the financial harm and mental anguish it says US citizens have suffered at the hands of an "ignoble tyrant". Spinning in a different direction, the London Evening Post assures readers that "our Sovereign Lord King George will defend the honour of the Crown when he appears in the lowly Boston courtroom of our former Massachusetts colony to repel the treacherous and unfounded accusations".

But there are contemporary issues at stake here. For example, how far should the domestic courts of one country exercise jurisdiction over the actions of foreign states and their leaders? Does a head of state – such as George III or Augusto Pinochet – have immunity for what they do while in office? And how far should the courts control the multinational monopoly corporations? These issues will be explored by panellists including the US Supreme Court Justice Stephen Breyer and District Judge Thomas Penfield Jackson, who is overseeing the anti-trust case against Microsoft. It should be an historic day.

Joshua Rozenberg is the BBC's legal affairs correspondent. He can be contacted at