What belligerents may do with a hospital ship

How does the law of war apply when a hospital ship is captured?

The captor verifies the ship's protected status and normally lets a genuine hospital ship continue, while an impostor may be detained.

A hospital-ship designation requires verification when an opposing force intercepts the vessel. The wartime example concerns German and Italian attempts to move ships from North Africa to Europe after their land forces collapsed. Boarding allows the intercepting force to establish whether a vessel is genuinely serving as a hospital ship. In this account, a verified medical vessel must be allowed through, while a ship falsely claiming that protection can be impounded.