Worboys victims 'learned of his release through media'
Victims of serial sex attacker John Worboys learned about his release from prison from the media, a review found.
Many victims were "shocked and distressed" to see the Parole Board's decision in news headlines, Chief Inspector of Probation Dame Glenys Stacey's paper said.
Her comments come as part of a review requested by the government into the "victim contact scheme".
Two victims are set to begin a High Court battle against releasing Worboys.
Dame Glenys's paper said "poor" correspondence included letters with errors in the women's names and addresses.
She said the National Probation Scheme (NPS) "generally complied with the scheme provisions", but that these mistakes suggested "a lack of care or concern".
"Those women not in contact with the scheme - the majority - learnt of the decision through the media. All who spoke to us described their shock and distress," she added.
"They had not felt prepared for this outcome."
Worboys, 60, was convicted of 19 offences in 2009.
He drugged his female victims before attacking them in his black cab.
Before Worboys's parole hearing, the NPS attempted to contact women who had not opted into the victim contact scheme.
But there was not enough time before the hearing for them to receive or absorb the letters, the report said.
"What is more, the style and content of the letters lacked clarity and urgency," it added.
"One woman who had engaged with the scheme from the start did make a Victim Personal Statement to the Parole Board.
"Others who we interviewed were adamant that they would have wanted to do so, had they had the opportunity."
What is the Victim Contact Scheme?
The VCS, run by the NPS, supports victims of violent or sexual crimes where the defendant is sentenced to at least a year in prison or has been detained under the Mental Health Act.
After defendants are convicted, victims are asked if they want to opt into the scheme.
If they do, they are given a Victim Liaison Officer (VLO) who keeps them informed about the offender.
Updates might include a release date, licence conditions, or if the convict is moved to an open prison.
Through the scheme victims are also able to make representations about an offender's release arrangements.
Dame Glenys' report found liaison between the VLO and John Worboys' offender manager was "poor".
Justice Secretary David Gauke said the report would help the government "review parole transparency and victim contact".
He said he was reassured that correct procedures were followed but that "we can do much better".
"We have already changed the letters we send to victims to make them more compassionate, clearer and more informative, but there is more to do," he added.