Interesting question…

I’ve always though the key point that turned the outcome of the War in Europe and ultimately dealt the winning hand that put an end to the Nazi threat, was the Battle of Britain. As Mr Boyle pointed out, without this little island fortress, there would have been no D-Day…

Another key part, without which the Battle of Britain might have taken another, less desirable path was Rolls-Royce’s Merlin… 😉