A 25-year-old woman who killed her baby boy by poisoning him with drugs has been jailed for three years.

Kelly Tugwell, of Gorse Avenue, Chatham, had previously pleaded guilty to the manslaughter of her young son when she appeared at Maidstone Crown Court on June 12.

She was jailed by a judge at Croydon Crown Court on Thursday.

Her son, Robert Williams, known as Junior, was just 19 months old when he was found dead on August 1 2004. He had been given Valium and a heroin substitute called Subutex.

Initially Tugwell, who is a drug addict, denied any involvement in her son’s death. When toxicology tests showed Junior had Valium present in his body, Tugwell then suggested the boy may have picked up and taken a tablet.

The toxicology tests also showed what had killed him was being given the drug combined with an adult dose of the heroin substitute Subutex.

The combined drugs administered by Tugwell to pacify her baby had caused Junior to suffer fatal respiratory failure.

The officer in the case, Det Insp Janine Chaney, sent a sample of Junior’s hair for specialist forensic tests to Strasbourg in France. These tests showed the boy had been given Valium on several occasions over a period of time.

DI Chaney said after the case that Junior had been left alone to die while Tugwell engaged in her drug and alcohol activities.

She added: "Tugwell did not intend to kill her child but tried to pacify him with drugs repeatedly which ultimately killed him when combined with the heroin substitute. This is a terrible and tragic case which has affected many people’s lives.

"I would like to thank all the forensic experts, the other agencies involved, the Crown Prosecution Service and counsel, and my team for bringing this case to a successful conclusion and for giving little Junior the justice he deserves."