Alderman Ian Luder, Lord Mayor of London in 2008-9, has been elected foreman of the Guildable Manor of Southwark.
He succeeds former BBC International Mastermind champion Leslie Grout.
This was the first time that court of Guildable Manor, covering the Borough Market area, has been convened at the church.
But it was the last to be presided over by Southwark High Steward Brian Barker who retires next spring as Recorder of London.
The jurors presented the retiring High Steward with a copy of Southwark and the City by David Johnson.
Judge Nicholas Hilliard, who has been appointed the next Recorder of London, is expected to be confirmed as High Steward shortly before Easter.
Since 1804 it has been the convention for the Recorder to also take on the role of Southwark's High Steward at the invitation of the City of London's Aldermanic Court.
In 2003 Judge Hilliard, at present Common Serjeant of London, was prosecuting barrister in the Who Wants To Be A Millionaire? coughing major trial at Southwark Crown Court.
Judge Barker's final 'charge to the jurors', took the form of an address on the significance of Magna Carta during which he urged jurors to take part in next year's celebrations marking the 800th anniversary of its sealing.
New manor officers include Southwark Cathedral parish clerk Robin Sherlock who was presented with a platter, knife and fork on becoming flesh taster.
The High Bailiff of Southwark Charles Henty read aloud the Riot Act which was passed three hundred years ago this year.
Afterwards Judge Barker made the short journey to Redcross Way to preside over a sitting of the King's Manor court leet at the Boot & Flogger.
Earlier in the day there had been a sitting of the Great Liberty court in the judges' dining room at the Inner London Crown Court in Newington Causeway.
A High Steward first presided over Southwark's three courts leet, a relic of the City of London's jurisdiction in Southwark, in 1550.
A recurring concern before the High Steward in the 1620s was the repair of pavements. In 1832 the issue was rubbish including the "emptying privies into gutter and throwing dead cats and dogs into the street".
Such matters, including weights and measures, are now the responsibility of Southwark Council.
Ald Luder first attended a Guildable Manor function when serving as as Aldermanic Sheriff of the City of London.