Fort Grey is one of the defenses built off the west coast of Guernsey in anticipation of a Napoleonic Invasion. It is situated on a rock known as Chateau de Rocquaine in Rocquaine Bay, St Pierre du Bois. It is now known colloquially as the "Cup and Saucer" due to its distinctive shape, and houses the Guernsey Museum's Shipwreck Museum.
The fort, with its white tower was originally built as a defence by the British garrison in 1804 during the Napoleonic Wars. It was named after Charles Grey, 1st Earl Grey, who was Governor of Guernsey from 1797 to 1807.
The War Office in London sold Fort Grey to the States of Guernsey in 1891 for £185. During the German Occupation in World War II, the Germans occupied the fort, as they did most of the other fortifications in Guernsey.
It is now part of the Guernsey Museum and hosts the Shipwreck Museum. It contains a number of items of marine salvage from famous wrecks, including the MV Prosperity and Elwood Mead. The items also include a cannon from HMS Boreas that points towards the nearby rocks at Les Hanois where Boreas sank in 1807 with the loss of her captain and at least half her crew.