A knifeman who killed three people and attacked three others was hearing voices who threatened him, and once visited MI5’s London headquarters to ask them to stop “controlling him”, a court has been told. Valdo Calocane was suffering from paranoid schizophrenia when he “brutally” stabbed students Barnaby Webber and Grace O’Malley-Kumar, both 19, and school caretaker Ian Coates, 65, in Nottingham in the early hours of last June 13. Calocane has admitted three counts of manslaughter and three of attempted murder after hitting three other pedestrians, one of them from Newark, with a van he stole …