Not only was the British navy at that time safeguarding the liberties of mankind at sea, but its army in France was doing its share in safeguarding them on land. And the fact that Britain had to support this mighty army had its part in making British shipping at times almost an easy prey for the German submarines. For next in importance to maintaining the British Grand Fleet intact it was necessary to keep secure the channel crossing. Over this little strip of water were transported the men and the supplies from England to France that kept the German army at bay; to have suspended these communications, even for a brief period, would have meant that the Germans would have captured Paris, overrun the whole of France, and ended the war, at least the war on land. In the course of four years Great Britain transported about 20,000,000 people across the Channel without the loss of a single soul. She accomplished this only by constantly using many destroyers and other light surface craft as escorts for the transports. But this was not the only responsibility of the kind that rested on the overburdened British shoulders. There was another part of the seas in which, for practical and political reasons, the British destroyer fleet had to do protective duty. In the Mediterranean lay not only the trade routes to the East, but also the lines of supply which extended to Italy, to Egypt, to Palestine, and to Mesopotamia. If Germany could have cut off Italy's food and materials Italy would have been forced to withdraw from the war. The German and Austrian submarines, escaping from Austria's Adriatic ports, were constantly assailing this commerce, attempting to do this very thing. Moreover, the success of the German submarine campaign in these waters would have compelled the Allies to abandon the Salonika expedition, which would have left the Central Powers absolute masters of the Balkans and the Middle East. For these reasons it was necessary to maintain a considerable force of destroyers in the Mediterranean.