A serial rapist attacked 11 women and children during a rampage across the country after he was mistakenly freed from prison, officials have ­admitted.

Joseph McCann was found guilty of 37 charges at the Old Bailey on Friday after committing crimes described as the worst police had ever seen.

McCann, who is facing life in prison, will be sentenced on Monday.

Dr Jo Farrar, the head of the prisons and probation service, issued an unprecedented and “unreserved ­apology” after it emerged that ­McCann had wrongly been let out of prison shortly before his rampage.

On Friday retired judge who tried to protect the public from McCann a decade ago criticised the string of “clear errors” that led to his release.

Senior politicians led calls for an ­independent review into “shocking failures” surrounding the case.

Over two weeks in April and May, 34-year-old McCann snatched victims off the street and subjected them to barbaric sexual assaults at knifepoint.

His victims included a 71-year-old woman and an 11-year-old boy.