Emma Tustin, 32, is serving a 29-year prison sentence at HMP Peterborough after being convicted of Arthur’s murder at her home in Solihull, west Midlands, on December 3.
The evil stepmother killed the young boy by repeatedly slamming his head on a hard surface after she and his father Thomas Hughes, 29, force-fed him food laden with salt.
Details of Arthur’s cruel abuse and treatment, including being poisoned with salt, emerged during the Tustin’s trial at Coventry Crown Court and caused widespread shock, revulsion and grief.
The youngster had been subjected to months of ‘unimaginable’ abuse by Hughes and Tustin before he was murdered during lockdown on June 17 last year.
In one haunting video, Arthur was seen struggling to stand before slumping to the floor of the living room.
His father, Hughes, who was sentenced to 21 years in prison for manslaughter, is due to appeal against his sentence.
Both sentences will be also challenged by Attorney General Suella Braverman under the unduly lenient sentence scheme.
Tustin is currently housed at HMP Peterborough and Hughes at HMP Wakefield.