The Swan Hunter Vesper Thornycraft Shipyard started as an alliance of down on their luck naval and space ship builders that had been nearly destroyed during the Human-Covenant War. These companies got favor with the UNSC for their Prowler and Destroyer ship designs during the rearmament in the 2580's, and despite not having their own shipyards, these ships were produced by Reyes-McLees Shipyards, and soon enough the money gained from these designs allowed them to build their own shipyards and reinstate themselves as major shipyard builders, rivaling the Reyess-Mclees conglomerate. To this day they produce Prowlers, Destroyers and support ships for the UNSC and civillian markets.