After losing a boat (slow speed thankfully.... Jeep tailgate bore the brunt) due to failed hitch a few years ago, I was advised that you were allowed a secondary means of attachment, so we rig our trailers with a wire rope lanyard as well as breakaway.
It has to be longer than the breakaway, so when the brakes are applied (first) you are still attached by the secondary means, trailer to vehicle.
Been pulled for trailer checks a few times (most recently today by Police doing trailer checks at end of M4) and they have always been happy with this arrangement.