The Air Britain book on the DH Hornet has an entry for 64 Squadron in 1949: "During March 6, 12 and 13, Op 'Forth/Clyde involved the squadron to Bishopbriggs and Abbotsinch, when PII J Hartley with his No.2 flew under the Forth Bridge, taking cine film in the process. On his return he faced a cool reception, explaining in his defence that briefing had clearly stipulated not flying above 50 feet"