[Madhatter]

History shizara. It was a hiring of workers fair. Workers would wear various things so hirers could identify their profession. Normal average workers would wear a piece of mop on their hat, just a strand. There are actually a few mop fairs arounf the country, most are in parks though not in the main street like Stratfords.
Here in Atherstone our fair was called the statutes fair, and was on the square car park opposite the cattle market until the town redevelopment made it homeless.
I've been to Stratford mop a few times.