The British Men of Letters compound was the base of operation of the British branch of the Men of Letters. It was destroyed by Sam Winchester, Jody Mills and Walt with explosives after an assault on the compound.
Shortly after The Darkness and God reconciled and left the Earth, the British Men of Letters made the decision to start working on the monster problem in America, relocating some of their equipment and operatives to an abandoned factory they managed to transform into a secure compound.
The base is made up of a series of modular containers and includes accommodation, a computer room, meeting room, and an armory.
In The Raid, the British Men of Letters invite Sam Winchester to visit their compound and take part in Project V, a project centered around the extermination of all vampires in America. Already present are Mick Davies, McGillicuddy, Alton Morehead, Serena Colman, Pierce Moncrieff and Mary Winchester.
The project goes awry when their intel fails to anticipate them for an attack from the very vampires they were hunting. The Alpha Vampire breaks in and kills numerous staff members, but he is shot and killed by Sam with the help of Mick using the Colt. Despite the disaster, Sam agrees to work for the Brits just like his mother is.
In The British Invasion, Mick encounters Renny Rawlings at the compound, and learns that Doctor Hess wants Renny to accompany Mick on his final mission to recruit the American hunters, otherwise he must kill them. The mission fails and Renny ends up dead. When Mick returns to the compound he is confronted by Doctor Hess and Arthur Ketch.
When Mick tries to reason with Dr. Hess about the flaws of their special Code, Dr. Hess orders Arthur to shoot Mick point blank in the back of the head. As Doctor Hess discusses her intention to have the American hunters annihilated, Mick's body is visibly, half across the table with blood pooled under his head.
In The Memory Remains, Arthur Ketch is seen at the compound after successfully infiltrating and wiretapping the Men of Letters bunker. He calls Sam and Dean to inform them that Mick is absent and he will be the person they report to. After the call, Arthur listens to their conversation, and hears Dean insult his motorbike.
In Who We Are, as the British Men of Letters prepare a massive operation to wipe out all of the American hunters, a team of hunters led by Sam arrives, including Jody Mills, Roy and Walt. The hunters assault the facility, suffering losses but killing everyone inside. After the death of Doctor Hess, the hunters blow up the compound as they leave.
In War of the Worlds, after capturing the resurrected Arthur Ketch, Sam goes over the extensive files on a hard drive he took from the compound in an effort to confirm "Alexander's" story. The files on the hard drive contain information on the Kendricks Academy and its graduates.
- In The Raid, Mary Winchester states that the British claim that the compound is only a temporary base of operations. Mary also states that the British act like they're "living rough" by using the compound.
- In The Raid, during the raid on the compound, Mary states that it is not built for defense. This is later seen again in Who We Are when Sam's assault team has little trouble penetrating the defenses.