Profiling failure
During Colin Stagg's time in prison, Ms Nickell's real murderer, Robert Napper, right, went on to kill another young mother and was finally convicted 16 years later.
Mr Justice Ognell criticised the investigation, saying: "This operation was sustained in constant consultation with the psychologist, the policewoman was acting under orders and the police in their turn were being guided by the psychologist."
However, criminal profiling techniques have changed dramatically in the 18 years since Ms Nickell's murder and the National Policing Improvement Agency came into being only in 2007.