LAURENCE REES: It seems extraordinary really, but Hitler seemed to have no real definite plan as to how he was going to defeat Great Britain.

GEOFFREY WAWRO: He had a real opportunity at Dunkirk, and it’s often been discussed why didn’t he send the Panzers right down to the beach and finish the job. Of course the Panzers were exhausted, ammunition stocks were depleted, fuel was low, there were maintenance issues and the troops needed a rest, so he decided to go with the Luftwaffe and the infantry. I think that the controversy is that it’s hard to imagine that the British wouldn't have been able to evacuate a fraction of their army and a fraction of the French army, anyway. And I think still the larger question is, even so, the British were going to retreat behind the moat of the English Channel. They were going to have the RAF, they were going to have the Royal Navy, they were going to hang on one way or the other. They could mobilise troops at home, they could mobilise colonial troops and they could rebuild. I think Dunkirk has tremendous morale significance for the British because even in this darkest hour of defeat there is this small little victory they can cling on to - that they’ve removed these men from battle and they’re ready and fit to fight another day.

Someone like Field Marshall Göring who was in command of the Luftwaffe, said we don’t need the Navy because airforces have rendered navies obsolete, so we’ll win command of the sea from the air. So the Blitz and the Battle of Britain, this was all to demonstrate the power of the Luftwaffe and its ability to control the sea lanes between the continent and Great Britain. But the British won the Battle of Britain and threw the Luftwaffe back, and then from that point forward Hitler had to abandon operation Sealion and all hope of invading the British Isles.