St Ninian's Isle is a small tied island connected by the largest tombolo in the UK[2] to the south-western coast of the Mainland, Shetland, in Scotland.

The important early medieval St Ninian's Isle Treasure of metalwork, mostly in silver, was discovered under the church floor in 1958.

However, the island's history is far older than Christianity, and Neolithic graves have been found within the walls of the chapel (formerly beneath the floor).

In 1958, an excavation found a hoard of 8th century silver in the chapel grounds under a stone slab in a wooden box, which caused a renewed archaeological interest in the island.

Coutts was helping visiting archaeologists led by Professor A. C. O'Dell of Aberdeen University at a dig on the isle.