A primary school teacher who murdered her boyfriend and buried his body in their back garden in a “carefully planned domestic execution” has been sentenced to life in prison with a minimum term of 20 years. Fiona Beal, 50, stabbed and killed her partner, Nicholas Billingham, 42, at their home in Northampton in 2021. His remains were discovered in March 2022, four and a half months after he had last been seen. The murder and cover-up happened while Beal claimed she was off work due to Covid, and she afterwards continued “to deliver high-quality teaching to year 6 pupils as if nothing had happened”, prosecutor Hugh Davies KC said. Beal originally denied murder and pleaded guilty to manslaughter, but changed her plea and admitted murder part-way through her trial at the Old Bailey in April. The trial heard how police had uncovered Beal’s actions, and discovered Billingham’s body, after reading entries in her diary in which she had written: “Moving a body is much more difficult than it looks on TV.” On Thursday, Judge Mark Lucraft KC handed Beal a life sentence and told her: “Not only did you kill Nick Billingham, you intended to do so. Having moved and buried the body in the garden, you then lied to his mother, numerous friends, all his family and yours as to what you had done and where he was.” The defendant showed no emotion and had her head down as she left court. She previously claimed she was in a “coercive” relationship with Billingham, which left her “broken”. In a victim impact statement read to the court, Billingham’s mother, Yvonne Valentine, said Beal was “pure evil” and described having a Christmas drink with her on 23 December 2021, not knowing she was just feet from her son’s body. The judge described it as a “callous act”. Davies said Beal had lured her victim to bed on the promise of sex but instead stabbed him in the neck causing fatal blood loss, while he was likely tied to the bed with cable ties. She disposed of the body by burying him down the side of their home like “building waste”, Davies told the court. She covered her tracks by alleging the couple had Covid and needed to isolate, and sent text messages from Billingham’s phone pretending to be him. She later told friends and family that she had split up with Billingham, and he had left her because he was having an affair. On her return to work, Beal received sympathy from colleagues who had heard about the apparent break-up. Her mental health started to deteriorate in February 2022, and in a journal entry dated 12 February, she wrote: “I’m not a total monster. I know what I did.” The trigger for a decline in her mental health was probably a visit to her home by a police community support officer concerned for Billingham’s van that was parked near a tree during heavy storms in February 2022, nearly four months after the murder. In March, she rented a cabin in Cumbria and sent messages to family members that led them to be concerned for her wellbeing and to call police to check on her. In the cabin, police found Beal in a distressed state having self-harmed, and discovered journals containing a confession to the killing, as well as reference to her having a split personality and an alter ego she called Tulip 22. One entry read: “While he was in the bath I kept the knife in my dressing gown pocket and then I had it in the drawer next to the bed. I brought a chisel, bin bag and cable ties up too. I got him to wear an eye mask.” She went on: “My last words to him when he asked why, was that he was not going to do to (another female) what he had done to me.” The discovery of the journals triggered a police investigation, which soon established Billingham had not been seen or spoken to since the afternoon of 1 November 2021. Beal was arrested in March 2022 after police discovered Billingham’s mummified body buried in makeshift layers of sheeting and concrete, as well as a blood-stained mattress in the basement. Andrew Wheeler KC, defending, said Beal was of previous good character and had been a “fantastic” teacher, adding that she had a long history of depression.