Stephanie Horrocks, 27, and partner Mark McAndrew, 33, failed to seek medical help for nine-month-old Perrin Barlow before he died in July 2002, Plymouth Crown Court was told.

Fellow addict McAndrew, who is not the child's natural father, was jailed for 15 months.

An investigation involving police and social services will be held into Perrin's death.

The couple, from Camperdown Street, Plymouth, both admitted child cruelty charges at an earlier hearing.

Urgent need

The court heard that when Horrocks took the baby to a child's birthday party on the afternoon of his death he seemed lethargic, unwell and vomited copiously. Friends at the party urged her to take him to a doctor.

Paul Dunkels, QC, prosecuting, said: "It was obvious even to those who didn't know Perrin that he was in need of urgent medical attention."

Paramedics were called to the couple's home later that night after Perrin stopped breathing.

The child - wearing only a soiled nappy - was taken to Derriford Hospital in Plymouth, but staff could not revive him.

In care

Medical tests carried out after Perrin's death showed he was suffering from bronchial pneumonia, was underweight and had signs of dehydration.

Perrin's death came less than four months after he was admitted to hospital for 20 days because he was underweight, the court heard.

Her other five children have been taken into care.

The court also heard that Horrocks had a conviction in 1996 for failing to call the emergency services after one of her children overdosed on her methadone, a heroin substitute.

Richard Smith QC, defending Horrocks, said her neglect of Perrin had not been deliberate.