PAKISTAN 1948-56 15r blue-green 'Khyber Pass' Proof, SG42Pakistan 1948 56 15r blue green 'Khyber Pass', IMPERFORATE lower left corner block of 12 (6x2) with plate number '1' and printers, De La Rue imprint, SG42. A fine unmounted mint corner block with full original gum. Some imperfections (crease between 5th and 6th vertical pairs, printer's marginal annotation in red affecting one unit and minor wrinkles). Despite this it remains an impressive and attractive quality piece. An important positional multiple