Mass murderer Robert Maudsley, who is serving a life sentence for brutally killing four people, has warned he'll kill again if he's ever released.
The monstrous killer, who is being held in Wakefield Prison, has already spent 40 years living in solitary confinement in a glass cage after he was deemed too dangerous to be around other prisoners.
But although he's previously complained his interment reminded him of a traumatic childhood, it has been reported he's now quite content living in the underground box.
