Siol nan Gaidheal (meaning 
Seed of the Gael), were formed as a Scottish nationalist organisation with a focus mainly on Scottish history, heritage and culture.  Formed in 
1978 as a faction within the 
Scottish National Party (SNP), they were made a proscribed organisation by the SNP leadership in the early 1980s along with the left leaning internal 
79 Group.
Many of their memebrs adopted a quasi-paramilitary look and would often burn the Union Jack at rallies and so on.
A successor organisation of the same name continues to exist.
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