What is the function of a Sam Browne belt?

In some countries (nowhere in the U.S., so far as I know), military and police uniforms have a feature known as a Sam Browne belt, which is a belt worn over the uniform coat, around the waist, with a thin strap looping over one shoulder.

Why? I suppose the shoulder-strap holds the waist-belt in place, but what is the point of the waist-belt?

When I was in the service a Sam Browne belt was an equipment belt, i.e. a belt to which one attached equipment, such as canteens, holsters, etc.

From Sam Browne Belt, A full history and a controversy:

Originally, it was so you’d carry your sidearm (sword or pistol) on the belt outside of your jacket. And thus the diagonal auxiliary strap, so the weight of said sidearm wouldn’t sag the waist belt to one side.

Eventually the holster/scabbard was lost except in exceptional ocassions, and the Sam Browne acquired the approximate military usefulness of a necktie, i.e. it looks sharp.

Originally, it was so you’d carry your sidearm (sword or pistol) on the belt outside of your jacket. And thus the diagonal auxiliary strap, so the weight of said sidearm wouldn’t sag the waist belt to one side.

Eventually the holster/scabbard was lost except in exceptional ocassions, and the Sam Browne acquired the approximate military usefulness of a necktie, i.e. it looks sharp.

The Mounties still use the Sam Browne for their red serge uniforms, and when they do, they carry a holster on the belt, along with a white lanyard to the pistol. (Originally the lanyard was in case the officer dropped the pistol while riding his horse.)

Here’s some pictures from the RCMP Musical Ride. Some of the more detailed pics show the belt, holster and lanyard. Also, you can tell from the way the Sam Browne is worn if the officer is non-comm or commissioned: non-comms wear the strap over the left shoulder, commissioned officers wear it over the right shoulder.

NJ State Troopers have a Sam Brown.

…non-comms wear the strap over the left shoulder, commissioned officers wear it over the right shoulder.

Interesting difference, perhaps related to where a (right-handed) person would place a holster vs. where one would place a scabbard.