PL.1 (AI) (SG21)/CASTLE STREET SCOTS LOCAL. 1855 envelope used locally in Edinburgh with die 2 1d pl.1 lettered AI tied very fine almost complete strike CASTLE STREET Scots Local type XVIII. On reverse Mae West "TOO LATE" hand stamp and Edinburgh date stamp JUL 27 1855. Filing fold affects stamp but of good appearance - MISSING IMPRIMATUR LETTERING. (Ref 105348).