Royal Mail Ship
It was used by many shipping lines , but is often associated in particular with the White Star Line , Cunard Line , Royal Mail Lines , Union-Castle Line , Canadian Pacific Line , Orient Line and the P&OSNC which held a number of high-profile mail contracts , and traditionally prefixed the names of many of their ships with the initials "RMS" . 
<triplet> White Star Line <subj> Royal Mail Lines <obj> owned by