Answer:
The British blockade of Germany during World War 1 was vital in the defeat of the central powers and without it, the war would have probably been a lot bloodier and maybe even longer. We can say with certainty today that it was justified but at the beginning of the war, it was not yet obvious that the war would be so bloody. Even with a great shortage of materials, food and other supplies, they extended the war to 1918. If they did not have those restrictions then who knows how much more blood would have to be spilled.