Notably, they were the only unitary authorities created by the local government reforms of the 1970s in Great Britain; which otherwise applied a two-tier structure.
They did not form districts within the regions of Scotland because their remoteness made it unviable.
[1] Single-tier council areas were not created throughout the rest of Scotland until 1996, under the Local Government etc.
In most of Scotland, from 1975 to 1996, local government areas consisted of regions and districts.
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