24th Feb 2013 - Culture Crash
Blackening faces is apparently a tradition for Morris dancers in the England/Wales border counties.
This from Wikipedia:
The usual explanation for the black face is that it is for "disguise", and that during the hard winters of the 17-18th Century out of work labourers and builders sought to anonymously supplement their income by a bit of dancing and begging.
Another theory is that the black face tradition derives from earlier forms of the dance involving a Moroccan king and his followers (which links into the theory that the word "morris" is derived from moorish or moresco). There is recorded evidence from 1688 of payments in Shrewsbury of 10 shillings to Ye Bedlam Morris and 2 shillings for Ye King of Morroco.