Slough House is the outpost where disgraced spies are banished to see out the rest of their derailed careers. Known as the 'slow horses' these misfits have committed crimes of drugs and drunkenness, lechery and failure, politics and betrayal while on duty.

In this drab and mildewed office these highly trained spies don't run ops, they push paper. Not one of them joined the Intelligence Service to be a slow horse and the one thing they have in common is they want to be back in the action.