i've heard of serco before, however, on a multi-national playing field, they aren't that much of a threat... yet.
it does bring up the greater question as to if it is wise to privatize prisons, detention centers, illegal alien deportation centers (big ass fucking catapults aimed at the ocean), military supply companies or the maintenance of weapon systems).
in the united states, there are similar corporations in operation, however, none so heavily diversified (with the exception of gm).
i'm sure we are all familiar with the pathology that drives the vast majority of corporations and in particular, the group mentality phenomenon: a group of people who by themselves, would not necessarily do absurdly fucked up things yet, when placed within a group of their peers and with a focus on the bottom line, tend to commit heinous criminal acts.