Alan Cartwright attacked his pal after the pair became embroiled in a drink-fuelled argument. The man suffered stab wounds and a collapsed lung which required hospital treatment.

Cartwright, 24, pled guilty to severely injuring his friend by striking him on the body with a knife.

The thug used to live in Vanguard Street, Clydebank, but his address was given as Main Street, Alexandria, when he appeared at Dumbarton Sheriff Court last week for sentencing.

Sarah Healing, fiscal depute, told the court the incident took place at a flat in Irving Quadrant in the early hours of Boxing Day in 2013.

A young woman who lived in the flat began drinking alcohol with her friend at around 7.30pm on Christmas Day after putting her children to bed.

Cartwright and a friend joined them about 10pm and then the victim and another man arrived at 4.15am.

The court heard that, soon afterwards, Cartwright and the victim started arguing.

Ms Healing continued: “During the course of the argument the accused picked up a knife and struck (the victim) twice on the back.

“They continued arguing with each other at which point two witnesses intervened to try and calm things down.

“(The victim) entered the kitchen and removed his upper clothing to find that he was bleeding from injuries to his back.” Cartwright started apologising for his actions while those present in the flat tried to persuade the man to get medical help. Initially he refused but soon started having breathing difficulties and an ambulance was called.

Police arrived and started questioning those present and the victim was taken to the Western Infirmary in Glasgow.

He had two stab wounds to the rear of the chest wall, both around three centimetres long.

Following a chest x-ray he was also found to have a collapsed right lung which required a chest drain to remove the fluid and reinflate the organ.

The court heard police also spoke to the man in hospital but he refused to identify who had attacked him.

Cartwright was arrested in relation to other matters and taken to Clydebank Police Station, where he was later told he was a suspect in the attack.

Tom Brown, defending, said: “He accepts this is a serious matter. He has previous convictions but there has been a gap since 2008.

“The person is a close friend of his. He does not know what sparked it off.

“He is utterly ashamed of the way he behaved. Immediately after the incident he was apologising to people about his behaviour and about what he had done. He is very remorseful.” Mr Brown added: “This has been a huge wake-up call for him. He wants to get his life back in order.” Sentencing Cartwright to 18 months in prison, Sheriff William Gallagher said the case was “extraordinary” and told him: “You are not able to give any detail as to why you did this.

“What you did on this occasion was to arm yourself with a knife and carry out an assault on another person, causing damage to his back and lung.

“Those who choose to resort to weapons of this type will find the court will find this behaviour cannot be accepted. This is a very serious matter indeed.” Members of Cartwright’s family sobbed as he was led away from the dock to begin his sentence.