A man shopped himself to police when he became angry in Gainsborough town centre while armed with a knife, a court was told.
Scott Cooper called police to say that he was in Gainsborough Market Place and wanted to hurt someone.
Edna Leonard, prosecuting, told Lincoln Crown Court: “The defendant said that he was in possession of a knife and he was angry.
“Officers went to the Market Place in Gainsborough and he was found sitting on a bench.
“When he saw the police he ran off but was detained shortly afterwards.
“He was searched. He had a Stanley knife in the rear pocket of his tracksuit bottoms and he was arrested.”
Cooper , aged 27, of Trinity View, Gainsborough, admitted possession of a bladed article in a public place as a result of the incident on March 8.
He also admitted breach of a suspended jail sentence imposed for harassment.
Judge Simon Hirst jailed Cooper for 15 months.
The judge told him: “Your previous record is dreadful. The only sentence I can impose is an immediate custodial sentence.”
David Eager, in mitigation, said Cooper was a potential danger to himself.
“In this instance he phoned the police himself.
“He is a young man with grave problems.
“He is an insulin-dependant diabetic who doesn’t take his medication.”