Unst is the northernmost inhabited island in the British Isles. If you want to be somewhere genuinely remote, this is the place. The island is reached by two short ferry crossings — Mainland to Yell, then Yell to Unst.
The main draw is Hermaness National Nature Reserve on the northern tip, where huge cliffs drop into the sea and thousands of seabirds — puffins, gannets, great skuas — nest in summer. The walk to the cliff edge crosses open moorland and takes about an hour. From the headland you can see Muckle Flugga lighthouse and Out Stack, the most northerly point of Britain.
There are a few small communities on the island, a heritage centre at Haroldswick, and a tiny airfield with flights to Tingwall (near Lerwick).