Originally Posted by
Onceapilot
The RAF seemed to agonise about cannon and the Spitfire had to wait for the MkVb to get 20mm cannon in the wings,
OAP
Not quite correct I am afraid. 19 Squadron had Spitfire Mk1bs with cannon in May/June 1940, but suffered from problems with their operation. I remember reading somewhere years ago that a pilot fired on a ME 109 ( and I am sure this was over Dunkirk) and immediately the windscreen of his Spit turned red!
There was also a Hurricane at North Weald called the 'old cow' (IIRC) with 20mm cannon ,that was somewhat slower @300mph than the Browning armed ones. It has been suggested by numerous BoB pilots, that had cannon fighters been more available, the outcome would have been even more decisive.