More, this time from Roy Dommet's paper for the Roots of Border Morris conference, organised by the Morris Federation at West Malvern on 29th February 1992:

The Nigger Minstrel character was created in the early 19th century and was extremely popular as an entertainment for the masses in the UK from the mid 19th century to the start of WW1. It soon became a folk entertainment and replaced or followed the mummers in many places up till WW11, being at its most popular in the 1920's. The show was easy to put on, it had a simple formal structure built around individual rather than group skills, and was easily mobile. It needed a leader and end-men and used songs, solo dances and simple skits. Without more research, it is not clear whether Minstrels were acceptable because they picked up elements of existing Christmas traditions like the morris or if the Border groups had gathered attributes from the Minstrels. There are references to the troupes singing and stepping.

Colouring the face introduce problems. When it is all over or nearly so can be quite frightening to children. Why do people find it disturbing? Clowns have patterned faces. Blacking up can also be seen as racist and some clubs have had difficulties with their local police, hence a number of non-black colour choices.

As a complete aside, Dooley Wilson, of As Time Goes By, Casablanca fame, was born Arthur Wilson but nicknamed Dooley because he used to perform Irish songs in whiteface make-up.