Bendall used a claw hammer to kill 35-year-old Terri Harris, her 11-year-old daughter Lacey Bennett, her son John Paul Bennett, 13, and Lacey's friend Connie Gent, 11.

Bendall also admitted raping Lacey during the attack, which took place in September last year at the home he shared with Ms Harris in Killamarsh, Derbyshire.

The 32-year-old was sentenced to a whole-life order on Wednesday.

Bendall was in the probation system for arson, robbery, attempted robbery and grievous bodily harm convictions and was serving a 24-month suspended sentence when he carried out the murders.

The Daily Telegraph reported that the probation officer who assessed Bendall for sentencing in the arson case has been sacked for gross misconduct after categorising him as "medium risk" rather than "high risk".

Another probation officer was found guilty of misconduct after allocating the case to a trainee.

A spokesperson for the Ministry of Justice said: "These were appalling crimes and our thoughts remain with the victims' families.

"The deputy prime minister asked the chief inspector of probation to conduct a review of this case and we will respond further once this is published."

The review is likely to be released in the new year.

Former justice secretary Sir Robert Buckland, who left the post just three days before the Killamarsh killings, said: "I think we have to acknowledge that such an error is just an appalling failure.

"The ministry has to be as open and transparent as possible about why it happened, and most importantly to make sure the risk of that happening again is kept to a minimum, if not eliminated.

"Frankly, there should be processes in place that means various thresholds and tests would be met before that sort of fundamental mistake could be made."