Fort Grey, colloquially known as the "cup and saucer", is a Martello tower located on a rock in Rocquaine Bay in Saint Peter, Guernsey. The French name of the rock upon which the tower was built is the Château de Rocquaine (Castle of Rocquaine); in Guernésiais Châté dé Rocquoïne. It was previously the site of local witches' Sabbaths. The existing fort, with its white tower was originally built as a defence by the British in 1804 during the Napoleonic Wars, it was named after Charles Grey, 1st Earl Grey, who was Governor of Guernsey from 1797 to 1807.