1911 FIRST OFFICIAL U.K. AERIAL POST LONDON ENVELOPE IN PURPLE-BROWN TO AMSTERDAM. Fine to very fine London envelope in purple-brown with insert to Amsterdam, with fine mixed reigns franking KEDVII 1½d purple and green and KGV 1d Downey tied fine strike 'FIRST UNITED KINGDOM/AERIAL POST/LONDON' date stamp SP 9 1911 Die 2. On reverse part Dutch date stamp 13.9.11. VERY FINE USAGE. (Ref 150758).
