The Lord Chancellor and the Master of the Rolls are to lead a procession at Runnymede to launch a countdown to the 800th anniversary of Magna Carta.
Kenneth Clarke and Lord Neuberger will be part of a gathering of "great pomp and circumstance" on Friday, according to Runnymede Borough Council.
Magna Carta was signed at Runnymede Meadows in Surrey on 15 June 1215.
The council said the 800th celebrations would show showcase Runnymede as the birthplace of modern democracy.
The procession, with a fanfare by Territorial Army trumpeters, will be from the entrance to the Magna Carta site to the memorial stone.
Alice Richmond, treasurer of the American Bar Association will be in the procession, along with mayors from across Surrey and Magna Carta's five charter towns of Canterbury, the City of London, Runnymede, St Albans and Edmundsbury.
The representatives of legal, constitutional, academic and political bodies will all be in ceremonial robes for the procession, which is open to the public.
'World Heritage status'
The council wants to set up a Magna Carta education centre and has called for a bank holiday to mark the 800th anniversary.
"For all residents in Runnymede this launch starts a chain of events that will leave a lasting legacy," said Councillor Derek Cotty.
"This area could achieve a World Heritage Site status for the significance of its role in modern democracy.
"The 800th celebrations diary will therefore put Runnymede entirely on the global map."
Magna Carta was a peace treaty between King John and the barons who were in revolt against him and set out the principles of freedom under the law.
Lord Neuberger, chairman of the Magna Carta Trust, said: "The importance of Magna Carta can never be understated.
"This document is the foundation stone of liberty, freedom, justice and democracy the world over."