Antarctica: British Antarctic Territory: 10th Anniversary of Antarctic Treaty 11/2p. gutter pair correctly franking 1974 (Mar. 7) envelope to Middlesex, tied by Argentine Islands F3 c.d.s’s with Apr. 29 ms. receiving note on reverse, large H.M.S. “Endurance” (Youle END1-04) and Argentine Islands boxed cachet (F-C-04) . SH 39 var., S.G. 38 var. Ex Leppard. A unique item. Heijtz notes that gutter pairs of 11/2p. and 4p. values are not known, the “11/2p. and 4p. probably all guillotined to sheets of 30”. This cover proves otherwise but we know of no other example. Photo. (Image1)