Welsh is British (but not English, unless we are talking pre-1914).
Skinheads are a group of British racists somewhere between the Westbro Baptists and the KKK but with political movements that are open and teaparty-esque. Their symbol is not a white robe but a shaven pate hence their name. As it was taken to be a symbol of their movement and was placed on many of their children it was banned in a similar fashion to children wearing swastikas. This is a cultural thing throughout Britain as most choose not to be shaven headed for fear of associating with the skinheads and so it affects few people other than those who wish to align that way. Lastly the skinheads are not common these days and really the shaven head is no longer representative of it, however it is still most commonly a style used by the lower financial end of the working class and especially in the more criminal areas in cities. The rules remain as a relic of this practice.
For a film representing the skinheads I recommend This is England (on the suggestion of others, having not actually seen it myself).
