Prime Minister Rishi Sunak has been challenged over the early release of dangerous criminals under a scheme aimed at easing overcrowding in jails.
During PMQs, Sir Keir Starmer asked for a guarantee that no criminals considered high risk were freed early.
The PM insisted no-one deemed a threat to public safety would be eligible.
But the Labour leader pointed to an example of one inmate who posed a danger to children, who had his release date brought forward.
The case was revealed in a report on HMP Lewes by the prisons watchdog, external, which was published on Tuesday.
The individual had a history of stalking and domestic abuse but was released without a full risk assessment.
The original scheme, introduced last October, allowed "low-level offenders" to be freed from prisons in England and Wales up to 18 days early under strict supervision.
This was increased to up to 60 days in March and will be further extended to up to 70 days from 23 May.
The government has said no-one convicted of a sexual, terrorist or serious violent offence would be eligible for early release.
The prison population has ballooned in recent decades as a result of tougher sentences and court backlogs.
Chief inspector of prisons Charlie Taylor has raised "serious concerns" about the policy.
His report highlighted one individual who had been freed early was recalled to custody before the watchdog's inspection of the prison had ended.
According to the findings, the inmate had a "significant" drug problem and a record of self-harm as well as experiencing suicidal thoughts, but was freed despite "appeals for the decision to be reversed and staff having serious concerns for his and the public's safety".