This FDC features the Great Britain 1961 Europa set (SG 626-628), cancelled with a Guernsey postmark on a cover that bears the wording ‘Isle of Jethou – Europa 1961 – First Day of Issue’. However, there are no actual Jethou local stamps anywhere on the envelope.
Part of the Bailiwick of Guernsey, Jethou is a small island, roughly half a mile long, that sits immediately south of Herm. It is owned by the Crown, but leased by a tenant.
Between 1960 and 1969, a period when the island was open to the public, Jethou issued its own local stamps. These were seemingly produced mainly to generate interest and publicity, though postally used examples, affixed to the back of mail from the island, do exist.
Islands within the Bailiwick were no longer allowed to produce their own local stamps once Guernsey gained postal independence in 1969, meaning that Jethou’s issues – like those from Herm – ceased.
Further background about Jethou stamps can be found on this website.