A DAD has been jailed for killing his 15-year-old son after shaking him when he was just a baby.

John Doak was jailed yesterday over the killing of Jack Mitchell, who was left disabled in the attack which unfolded in Laindon when he was four months old.

The attack happened in 2001 and left Jack wheelchair-bound having suffered severe traumatic brain injuries and battled cerebral palsy, epilepsy, curvature of the spine and blindness.

He required 24-hour care, was unable to talk, care or feed himself and Chelmsford Crown Court heard Jack’s quality of life was “very poor indeed, if not non-existent”.

Brave Jack was taken into foster care after the assault, but sadly died in 2016 with respiratory problems which an inquest ruled was the “effect of a historic non-accidental traumatic brain injury”.

Doak, 37, wept in the dock as he was sentenced for manslaughter and told he must serve three years in prison.

He arrived at court sporting a tattoo on his left hand with the name “Jack” written on it.

The court was told he had been left "devastated" by Jack's death.

His sentence was reduced from eight years as the lorry driver had already served four years for causing grievous bodily harm for the attack and admitted the killing on Friday.

However Mr Justice Cavanagh ruled Doak never “came clean about what happened” on that day and Jack endured “great suffering and low quality of life” as a result of the assault.

He said: “Jack was your son. He was born on January 19, 2001, and died aged 15 on 13 March 2016.

“However the cause of his death was a shaking-type assault you inflicted on Jack many years previously, on 22 May 2001, when he was only four months old.

“In the intervening period, Jack suffered from brain damage and from other very serious health problems that were the direct result of your assault.”

He added: “I have seen pictures of Jack as a baby and he was a lovely little boy. Tragically he did not have sufficient time for his personality to develop before the assault led to his severe disabilities.”

Prosecutor Philip Evans told the court Doak, now of Spalding, Lincolnshire, shook the boy when he was caring for Jack alone in Laindon, and the incident “would be outside the window of what would be described as rough handling”.

The boy was rushed to hospital on May 22, 2001, after being found unresponsive and taken to Great Ormond Street Hospital where his brain injuries were uncovered.

Doak was found guilty of one count of GBH and was sentenced to a four year prison term in 2002.

Jack was put in foster care in Harwich and Doak had no further contact with him. Jack died in Colchester Hospital in 2015.

Following an inquest Doak was re-arrested and charged with his murder, but admitted to manslaughter at the earliest opportunity.

Mr Evans said: “Had Jack not sustained brain injuries in 2001 which resulted in his ongoing difficulties he would not be expected to die from the infection in his chest.”