NoW paid PI to watch royals and celebrities
A private investigator has told the BBC that the News of the World paid him to follow Prince William secretly.
The prince was one of 100 high profile people, including politicians, celebrities and personalities close to the royal family, who were put under surveillance by the paper.
The News of the World, the paper at the heart of the phone hacking scandal, employed the investigator for a number of years.
Nick Higham reports.