Only the Army has them in reality. Army "Special Forces" wear a dark green beret in the garison evnvironment.
(USA) Member of the US Army Special Forces.
"Green Beret" is the nicknames, because of their headgear. Which is a green beret, though this is moreso on the US Special Forces, than the Royal Marines.
Don't mess with either of those fucking elites though. The green berets = 10 seconds from pwnage (if you're a terrorist)
Brit: I was a green beret, mate.
Fearless men who jump and die
Men who mean just what they say
The brave men of the Green Beret
Silver wings upon their chest
These are men, America's best
One hundred men will test today
But only three win the Green Beret
Trained to live off nature's land
Trained in combat, hand-to-hand
Men who fight by night and day
Courage peak from the Green Berets