The Chief Constable of Merseyside is to write to the home secretary condemning a decision to allow a convicted triple child killer to go on day release.
Chief Constable Bernard Hogan-Howe said life "should mean life"
David McGreavy has been allowed to walk around Liverpool unsupervised as part of preparations for his release from Ford Prison in Arundel, West Sussex.
Chief Constable Bernard Hogan-Howe said the decision was a "disgrace" and put children's safety at risk.
McGreavy, 54, was jailed in 1973 for murdering three children in Worcester.
He killed Paul Ralph, aged four, and his sisters Dawn, aged two, and nine-month-old Samantha before impaling their bodies on iron railings.
In a webcast broadcast on Friday evening on the Merseyside Police website, Mr Hogan-Howe said he believed a life sentence should mean life.
He added: "The fact that McGreavy has been given day release is a disgrace.
"He should not have been released.
"For me, why should society and in this case its children, take the risk that he offends again?
"Why should society take the risk that those who released him got it wrong?"
He added it was unlikely that McGreavy would be released in the Liverpool area as pictures of him had been published in local newspapers.
Mr Hogan-Howe's comments follow Worcester MP Michael Foster's call for McGreavy to be banned from entering that city as part of his release conditions.
The Home Office has said it is normal practice to allow a life prisoner out of prison temporarily before their release and that all prisoners are risk assessed first.