[George Hopp]

The RAF asked this same question in 1940, and found that both sides of the debate were correct to an extent. To clarify myself I will quote from the air testing of Bf 109 E-3, W.Nr. 1304, by the RAE in May and June 1940. This report is in "The Captive Luftwaffe" by Kenneth S. West, pp127-135:

"Mock dog-fights were staged between the Bf 109 and a Spitfire, both flown by pilots of the RAE. In addition, a number of fighter pilots, all of whom had recent operational flying experience, visited the RAE with their Spitfires and Hurricanes in order to obtain further combat practice. During these flights AE479 (W.Nr. 1304) was flown by RAE pilot, Flying Officer J.E. Pebody, who had completed the handling tests and was thoroughly familiar with it, and could thus be expected to get the best out of it. ...

"When the Bf 109 was following the Hurricane or Spitfire, it was found that the British aircraft turned inside the German machine without difficulty when flown by determined pilots who were not afraid to pull their aircraft round hard in a tight turn. In a surprisingly large number of cases, however, the Bf 109 succeeded in keeping on the tail of the Spitfire or Hurricane during these turning tests, merely because their pilots would not tighten up the turns sufficiently from fear of stalling and spinning. ...

"During the dog-fights against the Hurricane and Spitfire it became apparent that these fighters could out-turn the Bf 109 with ease when flown by determined pilots. Since the minimum radius of turn without height loss depends largely on stalling speed, and hence on wing loading, the poor turning performance of the Bf 109 may be ascribed to its high wing loading, 32.2 lb/sq ft compared with 24.8 lb/sq ft on the Spitfire. The minimum radius of turn without height loss was obtained by flying as near to the stall as possible at comparatively little g; this radius was about 696 ft on the Spitfire as against 885 ft on the Bf 109."

I hope this helps,
George