I'm not one, but this point occurred to me after a mull-over:
If evidence obtained illegally by a private citizen is admissible, then a private citizen could beat a confession out of a suspect and the confession would be admissible. Evidence obtained by aggravated assualt is illegally-obtained evidence.
Were this legal, the police would have picked up on it a long time ago. All a police officer would have to show in court was that (s)he didn't suborn any such beating.
“If evidence obtained illegally by a private citizen is admissible”
See “The Pentagon Papers”. Those were even marked “Top Secret”.
I think the leaked CRU info falls into the same category, only a lot more is at stake.
You won't find very many actual private citizens who'll do that.
And if they've got some sort of connection to the P.D., they're not a "private citizen". Off duty officers, for example, are still "the State" for Fourth Amendment purposes. I haven't seen a case, but I would think that P.D. employees and contractors would be in the same boat.
Freelance hackers are NOT state actors.
P.S. - there is no Fourth Amendment in Britain.
I think that evidence obtained illegally cannot be used in court, but since the authority did not obtain the evidence illegally, would it be probable cause for a search warrant?