Welcome to London's police force, with accusations of racism, the use of lethal force, and corruption all part of the daily routine. Luckily for the public, the capital city has the charismatic but uncompromising Commissioner Richard Miller at the helm, the man with the impossible job of keeping the capital safe.

But Miller has a secret weapon. Director of Communications Liz Garvey is a high-flying PR whizz from America, who's aim is to revolutionise the image of the police by dragging it into the new media age and throwing the doors open.

In an era where everyone with a phone is a cameraman, and crime is being reported on 24 hour rolling news before the police have received a 999 call, controlling the news agenda isn't easy. Particularly when your Communications deputy is the Machiavellian Finn, who's more used to trading stories with journalists over boozy lunches, and is determined to build the fortress walls higher. If that means bringing down the person who got what should have been his job, so be it...

Among Miller's other colleagues overseeing the city's streets from police HQ are Deputy Commissioner Charles Inglis and Assistant Commissioner Sharon Franklin, both with half an eye on the top job. And then there's Tom Oliver, Miller's loyal but faux pas prone assistant.

If life is tough in the rarefied atmosphere at the top, it's not much easier for the police on the streets below. Public Order Specialists Davina and Clarkey find their personal lives spilling over into the riot van; and in the Armed Response Unit, Tony and Banjo must contend with the increasingly fragile emotional state of Warwick, still reeling from shooting an unarmed man.

If the gun squad didn't have enough to deal with, Robbie moves closer to his dream of being a Firearms Officer - an eventuality to strike fear into all that know him.

Over it all, the quiet presence of documentary director Matt is lurking, filming, just waiting for the chance to capture an expose that will stun both police and public alike.