A THUG whose identity is being shielded despite a horrific broken bottle and bite attack on a train has been described as an 'extremely dangerous individual'.

The teenager — who can't be named because he remains just under the age of 18 — has racked up a dozen convictions for assault since June last year and has already been jailed twice before.

He is today beginning a further lengthy sentence for scarring a 51-year-old man for life in a shocking bout of extreme violence on the Wemyss Bay railway line, which has been blighted by anti-social behaviour and violence on numerous occasions.

The youth lashed out without warning, smashing a beer bottle into the victim's head before repeatedly sinking his teeth into the man who was returning home from a daytrip with his wife.

Sheriff Derek Hamilton told the terrorising teen: "You are a young man with a significant record.

"Since June 2017 you have three convictions for assault and nine for assaulting police officers."

Defence lawyer David Tod said: "He accepts the only thing that is going to happen to him and the only point of issue is how long his sentence should be."

Greenock Sheriff Court heard previously how the youth struck the man with the bottle fractionally above his left eye with such force that it smashed.

Prosecutor Pamela Brady said: "It left a large open wound to the man's forehead, from which her was bleeding heavily.

"There was also a small cut to his nose and a full thickness cut to his left ear as a result of this assault."

The man had only got up to move to another carriage with his wife due to the behaviour of the youth and a pal who was with him, the court was told.

He tried to restrain the teenager in case he inflicted further damage with the now jagged bottle but the out-of-control thug began to bite his fingers.

Police were alerted and were at Branchton to arrest him when the train pulled in there shortly after 8pm on July 14.

The youth — who caused the injured man to bleed so profusely that paramedics had to carry out emergency treatment at the station — brazenly told officers: "Aye, I bottled him."

Lawyer Mr Tod told the court: "He is heartily sorry.

"I have no instruction from him to make the commission of the offence sound any better."

The youth had been sentenced to six months detention for another assault just two days after the train attack and he was locked up in January for a 'number' of other serious matters.

Sheriff Hamilton imposed a sentence of 27 months and said that it would have been 36 months had there been no plea of guilty.

The sheriff said: "This was quite horrendous assault on an individual who was going home from a day's outing and was left with quite horrific injuries.

"I consider you to be an extremely dangerous individual."