Tracey Connelly was jailed for a minimum of five years in 2009, for causing the death of her tortured 17-month-old son Peter.
The case sparked outrage as Baby P received 60 visits from social workers, police and health professionals over a period of eight months.
Baby P was found dead in his cot at his home in Tottenham in 2007, after sustaining fatal injuries.
Tracey Connelly has been released from prison
Metropolitan Police
He had suffered more than 50 injuries, including fractured ribs and a broken back, inflicted by Connelly's parter Steven Barker and his brother Jason Owen.
Connelly was released on licence in 2013, but was recalled to prison just two years later for breaching her parole conditions.
Deputy Prime Minister and Justice Secretary, Dominic Raab said: “Tracey Connelly’s cruelty was pure evil, which is why I strongly opposed her release.
“The decision to let her out demonstrates why the Parole Board needs a fundamental overhaul, including a ministerial block, to protect the public and keep dangerous offenders off our streets.”
Boyfriend of Connelly, Steven Barker, and his brother, Jason Owen, were also imprisoned after being convicted in relation to Peter's death.
In March, the Parole Board, which is independent of the government, decided Connelly was fit for release, despite three bids for her to remain behind bars.
The decision had been made in 2021, but was paused while further repeorts and information were obtained.