A man who slashed his rival across the face with a knife could have "slashed his throat and killed him," a judge has said.
Violent Dwayne Anthony Leahy, 23, of Clarendon Road, Lancaster, had got into a fight with victim Josh Lloyd on September 30, Preston Crown Court was told.
Police were called around 11.45am by the Ambulance Service following reports a man had been attacked with a knife in an alleyway off Alexandra Road, Skerton, Lancaster.
The court heard Mr Lloyd did not make a police statement, but Leahy later admitted wounding.
Imposing a four year jail term, with an extended one year licence, Recorder A Hudson said: "In the circumstances I'm afraid I do agree there is a considerable risk to the public of serious harm and I do consider the dangerousness criteria are met.
She added: "You slashed him to the face before getting your girlfriend at the time to dispose of that knife.
"I've seen photographs of the injury and it is a huge injury which will inevitably cause permanent disfigurement.
"It is aggravated by your record, by the fact you were on licence, and the fact you engaged your girlfriend to get rid of that weapon. You do have violence on your record.
"I am entirely satisfied the offence demonstrates an extre turn in your offending towards wanton and extreme violence.
"You made no effort to scare Mr Lloyd off with that knife, you simply went straight at him and slashed him.
"You could very easily have slashed straight through his throat and killed him.
The court was told he had a history of drug misuses and poor compliance with court orders.
A young girl sobbed in the dpck as Recorder Hudson said: " You are an intelligent man. You are clearly capable and you have achieved qualifications which you could have relied on but you chose not to.
"You've had opportunities but you've repeatedly chosen not to engage.
"You are now 24 and a lack of maturity is no longer a consideration."
Leahy will be eligible to apply for release after serving two thirds of the term, but will not be released if the parole board deems him a danger.