A TROUBLED mum who caused her son's death after violently shaking him has been jailed for four years.

Baby Jack was taken into care after his birth, but a month later he was returned to mum Joanne Mallinder, 37, by social services.

Then when the tot was just three-months-old he was rushed hospital with six fractures to his arms and legs and irreversible brain damage consistent with "shaken baby syndrome".

More than a year passed before baby Jack eventually died of his injuries, aged just 16 months, in March 2007. His mum was cleared of murder, but found guilty of manslaughter following a trial in Basildon Crown Court last November.

She wept in the dock at St Alban's Crown Court on Friday as she was sentenced to four years for killing her child.

Judge Philip Clegg QC said: "She is a very damaged lady with deep psychological problems who has sought to self-medicate with alcohol. She poses no risk to anyone except a baby left in her care.

"My heart goes out to her when you hear of the history she has had.

"You must have pulled the child violently out of the car seat by his right arm then shook him violently causing fractures and brain damage."

The judge said other people had described her as a "conscientious and loving mother".

He added: "Quite what caused you to act out of character it a complete mystery."

The court heard Mallinder had been in a car accident on February 13, 2006.

She took baby Jack out of his car seat before shaking him violently.

When Mallinder got to her home in Falcon Avenue, Grays, the tot stopped breathing and had no pulse. He was rushed to Basildon Hospital where his horrific injuries were found by doctors.

The baby was taken to London's Great Ormond Street hospital where he died 13 months later.

Defending Mallinder, Sally O'Neill QC who was the prosecutor in the case of Baby P, said Mallinder was a vulnerable woman who continued to maintain her innocence.

Mallinder of Leicester Road, Tilbury, will be on licence for a further four years at the end of her sentence.