By the time of the Munich Agreement in 1938, when the British government finally accepted that war with Germany was inevitable and was taking desperate efforts to re-arm, it was left to British and French secret services to catch up with the extent of German and Italian readiness for a conflict. No serious reconnaissance had been done, and by this time it was too late to use military aircraft for the job.
The British Secret Service (SIS and later MI6) had become concerned as early as 1930, but its warnings to Government went unheeded.
Finding a way to fill the intelligence gap was achieved by two former WW1 pilots and a Mexican/American arms dealer with a very shady past............
The story of "Winterbotham, Cotton and Miranda" will follow shortly......................