Over a billion passengers a year. And 19,000 employees. All facing a daily battle with the world's oldest subway system: the London Underground. This one-hour documentary provides a rare glimpse into the depths of the iconic Tube network that passengers don't see, as workers reveal the dilemmas and pressures that they must reconcile to keep this hugely complex and strained system running. Actors voice the precise words of the workers: train drivers, maintenance workers, station staff and controllers. They negotiate the difficulties of storing dead bodies after suicides and the hazards of an ageing infrastructure while fixing signal failures. They confront aggressive passengers and emergency incidents and try to make sense of a bewildering array of procedures and targets. Ever wondered why you've heard a 'good service' announcement over the tannoy when you've been stuck on a train for the last 10 minutes?