A man who inflicted catastrophic injuries on a weeks old baby had his jail sentence cut today on appeal following a similar outcome in another case.

Steven Davidson, 23, shook her and threw the baby, leaving her severely brain-damaged and needing round the clock care.

The child was is now two is unable to sit up or communicate and requires round-the-clock care.

Davidson, formerly of Bontine Avenue, Dumbarton, was earlier jailed for seven and a half years for the attack on the six-week-old child but judges at the Court of Criminal Appeal Court in Edinburgh reduced the prison term by nine months.

The decision follows an earlier ruling by appeal judges to reduce a seven and a half year sentence imposed on Stephen Sweeney, 27, of Blantyre, Lanarkshire, to five years and three months for a shaking attack on a five week old baby boy at a holiday village at Dunoon, in Argyll, in September 2013. The sentencing judge, John Morris QC, said the boy's life had been 'devastated'.

Davidson had been left in charge of the baby for a short time at a house in Dumbarton in October 2012.

His defence counsel, Ronnie Renucci, earlier told the sentencing judge Lady Scott that in 'a single moment of madness' he shook the child and threw her down on a sofa.

Davidson had been suffering from toothache and had been up most of the night. The baby had been changed and was sick and had to be changed again.

Lady Scott told Davidson at the High Court in Edinburgh that the victim 'suffered truly catastrophic injuries, causing very real danger to her life'.

The court heard she suffered a brain injury and is not able to sit unaided and cannot take solid food.

But he challenged the sentence imposed on him and appeal judges, Lord Brodie and Lord Drummond Young, reduced his jail term to six years and nine months.

His appeal counsel, Victoria Dow, pointed out it was a one-off incident caused by frustration and a loss of control.

She accepted that the catastrophic consequences for the child were of course relevant but the sentencing judge also had to have regard to the degree of culpability of the accused.

The sentencing judge also had to try and achieve comparative justice with penalties imposed in other cases.

Lord Brodie said that Davidson's case appeared to feature 'a more violent incident' than in the last appeal of its kind.

He said the appeal judges would have selected a started point in sentencing of eight years which would be reduced to six years and nine months to take account of his guilty plea.

Davidson earlier admitted assaulting the baby to her severe injury, permanent impairment and to the danger of her life. An allegation that he had attempted to murder her was deleted.