There are numerous, but sketchy, historic accounts of May Day festivities and Jack in the Green processions.  Most of these had ceased to take place by the early years of the 20th Century.
Many of the revivals seen i
n various towns and cities today, represent original local figures.
The City of London Jack has no such pedigree! 
The City Jack is based on a variety of descriptions and illustrations from early writings.
In the late 1970's Morris dancers from various sides would gather to dance-in the summer on May Day in the Guildhall Yard, Leadenhall Market and various pubs in the City in their lunchtime.
Dave Lobb and Greenwood Morris used to dance at dawn at Alexandra Palace then  bring their Jack into the City for an evening tour of London Wall and the Smithfield area.
Dave Lobb and Mick Skrzypiec of the Earls of Essex Morris Men were discussing old May Day customs over a pint one lunchtime and decided to make it an all-day event.  Thus the concept of the City of London Jack in the Green was born!
On the first occasion, in 1984, the Earls of Essex and Mick Skrzypiec in the Jack met at dawn on Wanstead Flats to see the sun rise.  After breakfast they travelled by commuter train into Liverpool Street and started the first City of London Jack in the Green procession.
At the same time others were researching similar May Day traditions elsewhere.
Subsequently members of other Morris teams and the Grand Order of Guisers (GOG) were regulars in the City and were later joined by the new Deptford Jack, Alan Pearson carrying the Greenwood Jack and the Jack from Royal Liberty Morris.
Gradually the Morris element was phased out in order to attain a closer resemblance to the original form.
Tradition has it that the City of London Jack only comes out on City working days, so not weekends or bank holidays or during more recent civil disturbances when the police advised against it.