Kate had a bully hell.
The pal said: "She was picked on because she was perfect - well turned out and a lovely person. She was not the type of person to stick up for herself.
"They saw something that they could pick on - and gangs of girls can be very nasty."
Until now the official line has been that Kate "didn't fit in" at the pounds 30,000-a-year Downe House school in Cold Ash, Berks.
The friend added: "The bullying was far worse than just knocking her schoolbooks out of her hands. "Poor Kate was lonely, homesick and frequently in tears."