The drug-addict daughter of a British playwright killed her son by allowing him to drink methadone, it was revealed yesterday. Lorraine Dunbar's son, Harris, was two years old when he swallowed a teaspoon of the heroin substitute and died. Witnesses said he would often hold his arms outstretched, as if demanding a fix, each time his mother took a dose, a court heard. Her life began to fall apart when, at the age of 11, her mother Andrea - who wrote the popular play Rita, Sue and Bob Too - died of a brain haemorrhage. Unable to cope with the loss, she began taking drugs and developed a craving that ultimately led her into prostitution. The birth of Harris, did little to halt her descent. She smoked crack cocaine and heroin in front of him and saw little wrong with it. In July last year, Harris swallowed a fatal dose of the drug while living with his mother in a bedsit. It was not clear last night whether Dunbar, 28, had given her son methadone or he had accidentally taken it. Yesterday, details of Dunbar's chaotic life were revealed as she was jailed for three years and nine months for causing the death of her son. Bradford Crown Court was told how she was taken into care soon after her mother died in 1990. She soon began experimenting with drugs, using her mother's inheritance to pay for her habit. By the time she gave birth to Harris in 2005, she had become an addict and was living in a room at a women's refuge in Bradford, West Yorkshire. She had also converted to Islam and changed her name to Samaya Rafiq. Prosecutor Andrew Robertson QC said: "A witness confirmed that the defendant allowed the child to play with her methadone bottles. When a friend challenged her she responded with words to the effect that there was no harm in it. "Hair tests confirmed in the last four months of his life, Harris had actually ingested methadone. "There is a suggestion he had developed a craving for it. One witness described him holding his arms out as his mother took her dose." On the day Harris died Dunbar was again smoking drugs. When a hostel worker came to her room he found her calling the emergency services as Harris lay still on the bed. He was pronounced dead at hospital an hour later. Mr Robertson said a post mortem examination revealed the amount of methadone identified in Harris equated to a 5ml teaspoon. In addition, Harris had also inhaled the smoke from heroin and crack cocaine. His DNA was found on three of Dunbar's methadone bottles, the court was told.