Falmouth teenager Alex Burgoyne has been jailed after being caught carrying weapons for the third time in four months.
Police say the 19-year-old's offending has been "escalating" over the last few months and believe he would have injured someone in the latest incident if challenged.
After an incident between him and a teenage girl at Dracaena playing fields on Thursday and reports from residents of a man carrying a large knife, officers found Burgoyne in the Lambs Lane area with knives in his possession.
He had been drinking and officers restrained, disarmed and arrested him.
Burgoyne, formerly of Trevaylor Road but who told the court he was on no fixed abode, appeared at Bodmin Magistrates on Saturday.
He pleaded guilty to possession of two knives and to breaching a drink banning order imposed last November.
He was sentenced to eight months prison because the gravity of the offence and his previous convictions.No separate penalty was imposed for the breach and the knives were forfeited and destroyed.
Sergeant Phil Binnie said: "We were able to act quickly because witnesses came forward quickly, which means we took a serious threat to the public off the streets at a very early stage before anyone got hurt.
"I am very pleased. I have no doubt, if challenged by someone, we could have seen injuries.
"There is only one reason to be in possession of weapons."
Burgoyne was sent to prison in January after being spotted with a knife by three children with a 12 inch blade.He had been drinking alcohol and was in breach of his banning order.
A 12 week suspended sentence was activated and he was given an additional 21 days for the knife offence.
But the day after being released he was found with an imitation firearm in Falmouth town centre and was given a further 12 week jail sentence.
Sergeant Phil Binnie said: "He has a spiraling offending history and is becoming a concern to us.
"This sort of behaviour will not be tolerated, it is totally unacceptable."
