Jamie Varley and Vickrum Digwa were among the notorious killers jailed in the UK last month.Varley inflicted a fatal sexual assault on the 13-month-old boy he had adopted and will now spend the rest of his life behind bars for the murder. Digwa stabbed Henry Nowak before telling callous lies about him, which resulted in police at the scene cuffing the victim as he lay on the ground dying.Other offenders put behind bars in June included a stepmother who killed a five-year-old child by forcing her into a scalding hot bath and a mum who her one-year-old son with a…