Not sure, but it comes off as being something akin to the time agency in the Jean Claude Van Damme movie "Timecop". In "the doctor dances" Jack reveals that the chula ship was a con to attract the time agency. I got the impression from this that they investigated temporal anomalies, artifacts in the wrong place, etc, which is how Jack has such an extensive knowledge of alien artifacts in Torchwood. In any case the agency is now defunct. In episode 1 of Torchwood series 2 when Hart and Jack are in the bar "catching up" Jack asks how the agency is, to which Hart replies "it was shut down...there are only 7 of us left now."