Submarines and clandestine special operations

How important was submarine insertion and recovery of special-operations personnel for the Royal Navy compared with other navies?

The exact share is unknowable, but submarines supported many covert insertions whose records reveal little or nothing about the transport method.

The Royal Navy's clandestine submarine work is under-recorded by design. Where wartime accounts mention agents appearing in inaccessible coastal areas, submarine insertion can be the most plausible explanation. This sits alongside commando operations and the varied unofficial initiatives of submarine crews.