A teenager who admits stabbing a nurse to death in a frenzied attack last year told a court yesterday he had rape fantasies and had wanted to carry out a gun rampage at a school where he had been bullied.

Trainee accountant Stuart Harling, 19, stabbed Cheryl Moss 70 times in a savage attack as she enjoyed a cigarette break at a hospital in Essex.

Moss, 33, was attacked so suddenly she did not even have time to scream as she was set upon outside St George?s Hospital in Hornchurch in April last year. Harling admits killing Moss, who had worked at the hospital for more than 10 years, but denies murder on the grounds of diminished responsibility. Under cross-examination at the Old Bailey, Harling, surrounded by six prison officers, said he was obsessed with violent video games and regularly surfed pornographic Web sites on killing, torture and death.

One of his favourite Web sites was called ?Psycopath.com?.

?When I was at school I thought about shooting people like in the Columbine thing,? Harling said, referring to the massacre at Columbine High School, Colorado, in April 1999 when two students shot dead 13 people and then killed themselves.