The answer is in Scotland and the island in question is Eigg.
At just over 8000 hectares, it is known as the jewel in the Hebridean crown for its spectacular beauty, with views across to the north-west of the Isle of Rum. Located due south of the Isle of Skye, Eigg is also known for its cultural and historical attractions.
This eco-friendly gem also boasts the first completely wind, water and sun-powered electricity grid in the world. Additionally, its pioneering move to become a community-owned island, purchased through the Eigg Heritage Trust in 1997, resulted in the preservation of nature, whilst the community has flourished and no doubt inspired other islands to do the same.
This island has been sold to the present owners by Vladi Private Islands in partnership with Knight Frank.
For more information about the island, see: http://isleofeigg.net