A drug-fuelled teenager who viciously beat a mentally ill man with a garden spade as he lay helpless in the street has been locked up for four years.

The 17-year-old exploded with rage and felled vulnerable Yasar Sadiq with a whack from the shovel before raining up to ten blows on his head and upper body late at night in Staveley Road, Ingrow, Keighley, Bradford Crown Court heard.

The Keighley youth, who was 16 at the time and cannot be named for legal reasons, fled the scene with his friends leaving Mr Sadiq, 34, with severe head, face and arm wounds, gaping to reveal tissue and bone.

The teenager pleaded guilty to wounding with intent to do grievous bodily harm and possession of an offensive weapon on April 6.

Prosecutor Duncan Ritchie said yesterday the defendant and other youths were out on the streets after police broke up a noisy party they were attending at around midnight.

He had taken drugs and alcohol and became enraged when Mr Sadiq kicked a girl's bag and threw a soft drink at another young woman after a member of the group asked him for skunk cannabis.

The teenager seized a spade from a nearby garden and struck Mr Sadiq forcefully to the back of the head as he was walking away.

He raised it above his head and struck him up to ten blows as he lay on the ground.

The group made off and police found Mr Sadiq close by with serious injuries.

The teenager began crying afterwards, saying: "I might have killed him. What do I do?"

Mr Sadiq needed 14 staples in his head, 13 stitches to his lip and 14 stitches to his sliced arm that bone showed through.

The court heard his mental health difficulties had deepened since the attack and he was now in a secure mental hospital.

Mr Ritchie said Mr Sadiq was already suffering from bipolar disorder associated with substance misuse.

He was then living independently, supported by a psychiatric nurse, but was now in the hospital intensive car unit.

The stress, pain and trauma of the attack had contributed to his relapse.

Barrister Sophie Drake said in mitigation that the teenager was very remorseful.

"It was a spur of the moment offence with a weapon seized in the heat of the moment," she said.

Mr Sadiq was a complete stranger and the youth had no idea he suffered from mental health problems.

The defendant was living in a hostel at the time, leading "a wild life" misusing drugs and alcohol.

Judge Jonathan Rose told him: "You used terrible, vicious violence towards a man with serious mental health issues.

"It was an explosion of rage that it is impossible for a rational or reasonable person to understand."

Judge Rose continued: "It is by chance that you are not in that dock for an offence of murder."