Why did Britain sent ships back-and-forth across the English Channel to France?

Britain sent ships back-and-forth across the English Channel to France primarily to support military operations and facilitate the movement of troops, supplies, and equipment during conflicts, particularly during World War II. This logistical effort was crucial for evacuating forces, such as during the Dunkirk evacuation in 1940, and for maintaining communication and supply lines between the two nations. Additionally, the transport of civilians and refugees was also a significant aspect of these maritime operations.