LMAO @ this thread!


Harbouring a criminal? err, not exactly, it's his flatmate...
Implicated in the crime because he 'knows about it'? - I'm not a lawyer, but I seriously doubt that, tbh. If I tell you I am going to kill my wife, and then I kill my wife, does that make you an accessory to murder? (I'm not planning to kill my wife btw, it's just an example...

)
If (and its a pretty big if) the OP were ever to be asked why he didn't report this to the Police, he could quite feasibly say 'listen, it was a late night drunken conversation, I didn't think he was actually serious about it...' and assuming the OP has no proceeds of the crime, I find it highly unlikely he'd get prosecuted for anything. To suggest he would be is a tad dramatic IMO.
Fair play to the OP for trying to alert those who could be affected.