Lord Mayor of London been mandatory for election to the Lord Mayoralty. Two Sheriffs are selected annually by Common Hall, which meets on Midsummer's Day for this purpose. By an ordinance of 1435, the Lord Mayor must be chosen from amongst the Aldermen of the City of London. Those on the electoral roll of each of the City's 25 Wards select one Alderman, who formerly held office for life or until resignation. Now each Alderman must submit for re-election at least once in every six years. The Lord Mayor is then sworn in November, on the day before the Lord Mayor's Show ("see below").
Lord Mayor of London State Robes by means of black or white silk satin ribbons on the shoulders. As an Alderman of the City of London the Lord Mayor has a scarlet gown and a violet gown, which are identical to those worn by his or her fellow aldermen except that they are trained. The violet robe is worn at most formal meetings of the Corporation with the scarlet robe substituted on certain days or occasions as directed by the City Ceremonial Book. For State occasions when the monarch is present, the Lord Mayor wears a crimson velvet robe of state trimmed with an