1943 registered censored airmail addressed to Switzerland internally redirected. Franked Great Britain 4d, 2d and a horizontal pair 1/2d adhesives tied oval 'REGISTERED BRITISH P.O. TANGIER' d/s '14 JU 43. At right side pink 'PC 93' seal applied in Gibraltar on detained registered mail with '2415' reference number. The envelope was delivered in January 1946. A rare seal with two or three known.