For those of you who haven't used a velcro inner belt, it's a bit of kit that will make you wonder why you ever tried messing around with belt keepers.
It goes under the belt loops of your trousers like a normal belt. Any duty belt with a corresponding velcro inner can then go over the top, causing them to cling together. This holds the belt firmly in place and stops your belt from riding up over your trousers and enables you to break into a foot pursuit without your belt bouncing all over the place. It also means that even if your belt buckle comes undone, your belt will be held in place long enough for you to do it back up again.
A simple but very effective bit of kit made by Price Western Leather.