The convicted burglar had been released from prison in February, despite being subject to an Imprisonment for Public Protection sentence.
After being convicted in 2008 for burglary with a knife, McCann should have been recalled to prison after a fresh burglary and theft conviction in 2017.
Following an internal investigation, the Ministry of Justice accepted he was freed in error.
McCann’s rampage began in Watford before moving on to London, Greater Manchester and Cheshire, with hundreds of officers being deployed in the manhunt.
He was finally caught hiding in a tree.
Detective Chief Inspector Katherine Goodwin, who led the investigation, said: “McCann is a depraved and extremely dangerous individual who subjected 11 innocent people to horrific sexual and physical assaults – the memory of which they will have to live with for the rest of their lives.
“This case is one of the most shocking I have ever worked on.”
