The Phase Factory was a factory bought by the Old Styx in Slough, England. The Styx used it as a multi-purpose base as they began to invade Topsoil, and as the Phase site. They use it to create the "human bombs" to kill foreign politicians and make England go under martial law. Later on, the Styx use it as a Phase impregnation site, where the Styx women can sucessfully put eggs into hosts and create Warrior Class Styx. It appears in Spiral.
The Factory was built sometime in the past in Slough, England. It was abandoned by its previous owners and put up for sale (not unusual for that area).
It first appears in Spiral, when it is revealed that the Old Styx bought the factory. With New Germanian and Styx guards and roadblocks, the Old Styx comments on how well the factory will suit their needs. The Rebeccas later arrive there with Vane, Alex, and the other Styx women. Rebecca One commences the Phase, and the women start to work on impregnating the Darklit Topsoiler and Colonist hosts. As the process moves on successfully, the Rebeccas act as ruthless bosses. The Styx Warrior class also started to absorb the human host, and they were developing.
Meanwhile, the Old Guard was getting information updates about where the new Phase site was. They eventually locate this site at the factory. Will, Drake, Parry, and co., along with the rest of the Old Guard, prepare an assault on the factory. With sharpshooters, trucks, and even soldiers in the sewers, Parry reveals his plans to burn the Styx larvae and stop the Phase. A battle ensues as the Old Guard attacks and kills many guards. While inside, Will is horrified by the Warrior Class Styx and the spider-like Styx women. During the assault they manage to kill a Styx army major and burn the larvae. The Old Guard flees after setting the factory on fire.
As Vane, Alex, and the Rebeccas drive away, one of the Rebeccas points out the burning remains of the factory. Vane is distraught at how all her eggs died in the attack.
The Factory consists of three main buildings, each shaped like a warehouse. They are hangar-sized and big enough to fit hundreds of Phase hosts in each building.