Pakistan's private security is thriving and worth well over half a billion dollars a year.<br /><br />The increase is largely due to the lack of government action, countless terror attacks and sporadic violence that the military and other law enforcement agencies struggle to contain.<br /><br />It is an industry that provides jobs for around 350 000 people, many of whom are poorly trained and badly paid - but that has not deterred its growth.<br /><br />Al Jazeera's Imtiaz Tyab reports from Karachi.