A woman who killed her six-year-old stepson, who had been poisoned, starved and beaten in the weeks before his death, has been sentenced to life in prison with a minimum term of 29 years. Emma Tustin, 32, was sentenced for the murder of Arthur Labinjo-Hughes, alongside his father, 29-year-old Thomas Hughes, who was given 21 years in prison for manslaughter. “Arthur was subjected to the most unimaginable suffering at the hands of both of you. You both told lies to conceal what was happening in that house. Your behaviour towards him was often spiteful and at times sadistic,” said Mr Justice Wall as he passed sentence at Coventry crown court on Friday. “This is without doubt one of the most distressing and disturbing cases with which I have had to deal.” The pair were convicted on Thursday after an eight-week trial that revealed how Arthur was subjected to “incomprehensible and escalating cruelty”, prosecutors argued. He was physically assaulted, poisoned with salt and forced to stand in isolation for up to 14 hours a day in the months leading up to his death. Wall described Tustin, who refused to come to the dock for the sentencing, as a “manipulative woman who will tell any lie and shift the blame on to anyone to save her own skin”. He said it was a “shocking feature of the case” that Tustin’s own two children, aged four and five, “lived a perfectly happy, normal life in that household while this appalling cruelty to Arthur was taking place”. Addressing Hughes, he said the father had apparently cared properly for Arthur “before you became infatuated with Tustin to the extent that it obliterated all your love for your son”. Tustin killed Arthur on 16 June last year by violently shaking and hitting his head, causing injuries that were “extensive and devastating”, Wall said. “The amount of violence you used on him produced forces on his body said to be equivalent to those which might otherwise have been produced by a high-speed road traffic collision.” Tustin poisoned Arthur with salt over a number of weeks, giving him a significant amount in the hours before his death. When he was admitted to hospital, the levels of sodium in his blood were so high they could not accurately be measured by hospital equipment, and 130 bruises were found on his body, a number described as “staggering” by a medical expert. An investigation has been launched into local social services, which failed to detect the abuse that began when Hughes moved into Tustin’s home in Solihull with his son during lockdown last year. Social workers visited Tustin’s house two months before Arthur’s death after concerns were raised by his grandmother, Joanne Hughes, about bruises on his back, but they concluded there were “no safeguarding concerns”. West Midlands police are also being investigated by the police watchdog for their actions after being forwarded photos of the bruises on Arthur’s body. In a victim impact statement read out in court before sentencing, Joanne Hughes said: “It is clear from the evidence that I have heard that Arthur was failed by the very authorities that we, as a society, are led to believe are there to ensure the safety of everyone.” The family said that prior to Tustin’s involvement Arthur was “the model of a happy, joyous, exuberant and loving six-year-old” who loved dressing up as superheroes, playing cricket and football, and they “would always remember him so”. Birmingham City, the football club Arthur supported, said it would encourage fans to take part in a minute’s applause in the sixth minute of its game against Millwall on Saturday in tribute to Arthur. Wall said “the mental image of Hughes deliberately ripping up [Arthur’s] beloved Birmingham City football shirt” was one of many that would “live with anyone who attended this trial for a very long time”. In messages to his partner, Hughes often referred to his son using expletives, and compared him to Hitler and Satan, part of a pattern of dehumanisation that enabled the abuse, the prosecution argued. “The less human he seemed to be, the more freedom you had to abuse him,” Wall said. Hughes’ encouragement of his partner’s actions was chilling, he said. “You were Arthur’s father, in a position of trust, and bore primary responsibility for protecting him.”