at Her Majesty's pleasure

prepositional phrase2

1. •
   Indefinitely; for an arbitrary period determined by the monarch or her government (especially for indefinite tenure or imprisonment).

   • The Governor serves at Her Majesty's pleasure.
   • The murderer was imprisoned at Her Majesty's pleasure.
2. •
   (informal) In prison.

   • He spent two years at Her Majesty's pleasure.