1948 REGISTERED MAIL LONDON TO CANADA/BPA ASSOC. Envelope sent registered mail London to Toronto with KGVI 2½d light ultramarine (SG489) and 3d pale violet (SG490) cancelled LONDON 23 JLY 48 with "PASSED BY BRITISH PHILATELIC ASSN...." cachet and STANLEY GIBBONS LTD/c/o BRITISH PHILATELIC ASSN.... label at left. (Ref 100553).