The history is very complicated. The issues were the right of succession following the deposition of James II of England, BPCs grandfather and the old chestnut that has blighted much of NW Europe since the 16th Century; the Roman Catholic v Protestant issue. So it was not as straight forward as Scotland v England and ironically the West Coast of Scotland, BPC's powerbase, was not brought under the control of the king based in Edinburgh until the 1540's.