Complex sentence: On 10 February 1972, the Island of Rockall Act received Royal Assent to make the island administratively part of the Isle of Harris (St. Kilda being administratively part of Harris), in what was then Inverness-shire, fully incorporating it into the United Kingdom.
Split into simpler sentences: On 10 February 1972, the Island of Rockall Act received Royal Assent. It made the island administratively part of the Isle of Harris (St. Kilda being administratively part of Harris), in what was then Inverness-shire, fully incorporating it into the United Kingdom.