Four different lighthouses were used to create what is seen in the movie as a singular location: Mull of Galloway lighthouse was used for exterior and interior cottages, lighthouse, lighthouse garden and the headland of the island. Killantrigan lighthouse was used for its interior staircase and side garden. Corsewall lighthouse was used for a single interior shot and to create the cliff for many of the cliff scenes. Cloch lighthouse was used for the interior lightroom as it is no longer operational, yet beautifully preserved.
Some of the films locations in South West Scotland are filmed at Scotland's most southerly point at the Mull of Galloway Lighthouse.
On their first night, the men eat freshly caught crab. At this point in time, shellfish was considered a poor person's meal. The fact that Donald has no idea how to eat it gives some background on his character.
A Doctor Who story, "The Horror Of Fang Rock," was loosely based on the mystery of the Flannen Isles lighthouse, which forms the basis of this film.