Being a Celt in British society renders you ethnic. You might then experience all the feelings of inferiority that potentially come from that. These are not the same identity issues an immigrant can have.

A Scot can feel as much a Brit as an English person while still not fully integrated and thus be subject to subtle alienation different from other ethnics whose cultural background creates a more easily identifiable gulf.

Dark skinned people in white society can be made to feel they are always in some way foreign even when several generations of their relations have lived here. Their separateness is determined by externals like skin colour and race. But the Scot feels natively foreign. This partly explains his hatred of the English and the intimidation he feels from south of the border's air of superiority.

The problems faced trying to overcome ethnic disadvantage are slightly different dependent on your minority status being external or internal. As an intern you are part of the family but forever the lesser sibling. As a foreigner you are always a foreigner.