In the Aeroplane Photo Supply catalog No. 17 this photo is identified as a de Havilland Hertfordshire.
02/29/2003. Remarks by Ed Coates: "The aircraft is the D.H.95 Flamingo. It had an all-metal stressed skin construction. The Hertfordshire was to have been a militarized version designed to carry 22 paratroops. Only the prototype was built."
02/30/2003. Remarks by Chris Young: "The photo is similar to one I found in an old Air Enthusiast magazine a few years back. It's a Flamingo rather than the sole Hertfordshire that de Havilland built. The photo shows AE444 (c/n 95005) carrying de Havilland test or 'Class B' marks E-16 undergoing single engine testing. It was an engine and propeller test bed. The military variant of the Flamingo with which de Havilland was trying to interest the Air Ministry with was being developed as the D.H.95 Hertfordshire. Only one was finished, being given the Air Ministry s/n R2510. Externally it differed from the civil examples by having oval cabin windows instead of rectangular ones. Internally, the Hertfordshire had seating for 22 paratroops sitting in bench seats along side the main cabin walls."