1911 FIRST U.K. AERIAL POST LONDON ENVELOPE IN PURPLE-BROWN TO HARPENDEN, HERTFORDSHIRE. Good to fine London envelope in purple-brown to 'J.C. Fitzgerald Esq., The Elmo, Station Road, Harpenden, Herts.', minor imperfections, with KGV 1d Downey tied good large part strike 'FIRST UNITED KINGDOM/AERIAL POST/LONDON' date stamp SP 9 1911 Die 3. On reverse 'HARPENDEN' date stamp SP 12 11. (Ref 150745).
