Why the Royal Navy would resist owning the French Channel coast

If France attacked Germany in 1913, would the Royal Navy support Germany in return for the French Channel coast?

Probably not. Britain benefited from denying hostile use of the coast, but owning it would require an enlarged army and an enduring continental defense commitment.

Strategic influence over a coastline differs from sovereign responsibility for it. A navy may want ports denied to an enemy without wanting to garrison and administer the territory itself. British possession would make the French Channel coast a land-defense problem and give the Army a strong case for permanent expansion. The counterfactual exposes the different burdens created by sea control, alliance policy, and territorial conquest.