John Worboys - who was a cab driver in the capital - was jailed in 2009 for assaulting 12 women but is suspected of attacking over 100.
He was jailed indefinitely, with a minimum term of eight years.
Jill Saward who died exactly a year ago and was the first rape survivor in Britain to waive her right to anonymity after she was attacked by intruders at her father's vicarage in 1986, branded the sentence a "disaster" back in 2009.
Her widower Gavin Drake told Premier how his wife would have reacted to his release.
Speaking during Premier's News Hour, he said: "I think she'd be horrified.
"She was one who campaigned and promoted the idea and the concept of forgiveness but also at the same time the concept of justice.
"These were not things that were in competition with each other but they were two sides of the same coin."
The chairman of the Parole Board has apologised "unreservedly" over the failure to inform the victims of Worboys' imminent release.
Professor Nick Hardwick said he fully accepts there was a problem with the parole system, and that it was believed the victims had been informed before the decision was issued.
Drake told Premier there were a number of reasons he disagreed with Worboys being released.
He explained: "It is an injustice and it's an injustice in part because of the secrecy."
"A man convicted of the offences that this particular offender had been convicted of should be serving a lot more than 10 years in prison... as a means of punishment [and] for the protection of women."
Prof Hardwick insisted the organisation holds victims "absolutely uppermost in our minds".
He said: "We recognise that we deal with some very dangerous people and we won't and can't release them until we are as confident as we can be that it is safe to do so.
"But in the end it is not an exact science.
"We look at a whole range of evidence, both what happened in the original offences, the judge's sentencing remarks, the programmes or work a prisoner has done, reports from people who know the prisoner well.
The 60-year-old serial sex offender will be subject to "stringent" licence conditions.
Listen to Gavin Drake speaking with Premier's Alex Williams:
