A club doorman, who inflicted serious head injuries on his baby son in a momentary fit of temper, was today starting a seven year jail sentence.

The 23-year-old father vigorously shook the eight-week-old infant and might also have thrown him down.

The boy, now aged nearly three, suffered a subdural haemorrhage and bleeding to the back of his eyes, and Bradford Crown Court heard that his long-term prognosis remains unclear.

The man, who cannot be named to protect the identity of the child, was yesterday convicted of causing him grievous bodily harm with intent. He looked shocked as the seven-year sentence was passed.

Judge David Hatton QC told the defendant: “The effects of your assault may not be known for a very long time.”

He said it was too early for a clear prognosis, but there were obvious risks to the boy’s intellectual functioning, and of epilepsy.

Judge Hatton said: “It’s clear you lost your temper and lost control, either as a result of his persistent crying, difficulty encountered in administering his medicines, and/or combined with the fact that at the same time he made a mess on your settee.

“The assault was clearly very forceful indeed and was perpetrated against a victim more vulnerable than most.”

The judge said he was satisfied there was not a background of abuse or violence. “What you did was not typical. It was a momentary loss of control, serious though it was.”

Prosecutor Nick Askins had told the jury the infant suffered serious head injuries the first time he was left alone with his father, while his mother, in her late teens, and his grandmother went shopping.

Paramedics called to the couple’s flat in Bradford at about 9.30pm on June 28, 2011, found the baby suffering seizures.

Mr Askins said the child was treated at Bradford Royal Infirmary and transferred to the paediatric intensive care unit at Leeds General Infirmary. He was discharged after about three weeks.

The defendant, who was arrested the day after the baby became ill, told police he called an ambulance immediately he realised something was wrong.

He told the jury, during his trial, he was preparing a bath for his son when the baby fell off the settee.

He said he found him face down on the floor and said the boy “must have rolled off.”

Mitigating, his barrister, Tahir Khan QC, said the defendant had acted completely out of character and instantly regretted what he had done.

He was a young man who had embraced parental responsibility and had played a full part in supporting his partner.

The court heard that a judge sitting in the Family Court had ruled the defendant should have no contact with his son until he was 18.