The Fleet Protection Group Royal Marines is the only operational Royal Marines unit outside 3 Commando Brigade. The Group works through the Commander Operations Fleet to the Commander-in-Chief Fleet, and is responsible for a wide range of tasks worldwide in support of the Royal Navy.

FPGRM is based at the HM Naval Base Clyde, which is situated near Helensburgh on the West Coast of Scotland. The Group is over 500 strong and is made up of 3 rifle squadrons (O, R and S) plus an HQ squadron.