Steven Davidson, 23, left the child requiring constant care after he shook her and threw her.

A judge told Davidson: “She suffered truly catastrophic injuries, causing very real danger to her life.” Lady Scott said his actions had resulted in truly terrible, tragic consequences.

The judge told him at the High Court in Edinburgh that he would have faced a nine-year sentence, but for his earlier guilty plea.

Davidson previously admitted shaking the baby and throwing her to her severe injury, permanent impairment, and to the danger of her life at a house in Dumbarton on October 3 in 2012. He had originally faced a charge of attempted murder.

Advocate depute Paul Kearney said: “She has an acquired brain injury which has left her with a severe physical disability.” The prosecutor said she was not able to sit unaided, cannot take solid food and will require a wheelchair.

He said: “Although aged two she functions at the level of a child of four or five months. She can make sounds, but cannot speak. She is described as an engaging child and can smile, laugh an cry and use facial expressions, but is otherwise unable to communicate, even though she clearly wants to.” The court heard that Davidson had been left in charge of the child for only a short period of time.

At the time of the attack on the baby Davidson was looking after the infant.

The child was later found to be unresponsive and emergency services were contacted. She was taken to hospital and a CT scan showed bleeding inside her skull.

Defence counsel Ronnie Renucci said first offender Davidson had accepted full responsibility for the offence in 'a truly tragic case’. He added that Davidson would regret it for the rest of his life.

He said Davidson had been suffering from toothache and had been up most of the night.

The baby had been changed and was then sick and had to be changed again.

Mr Renucci said that in 'a single moment of madness’ he shook the child once and threw her down on a sofa. He did not think that a soft sofa would cause such injuries.

The defence counsel said that it was a one-off isolated, catastrophic incident. He added: “It is a matter he deeply regrets.”