A homeless man brought a knife into court because he wanted to go back to jail.
Ian McCarthy refused to go through metal detectors arches or be scanned by G4S staff at Liverpool Crown Court .
He barged his way into the reception area and started waving the five inch blade around on November 28 this year.
But brave plainclothes police officers - not wearing protective body armour - tackled him to the ground and disarmed him.
The court today heard "institutionalised" McCarthy has been caught with knives or offensive weapons on 11 occasions.
Defence lawyer Gary Lawrenson said the 55-year-old had only been released from prison a few days earlier.
He said he couldn't cope on the outside and wished to be sent back to jail, adding: "Obviously your honour will oblige."
McCarthy, formerly of Croxteth Road, Toxteth , pleaded guilty to threatening a person with a blade in a public place.
Christopher Hopkins, prosecuting, said the court - which was put on lockdown with murder trials interrupted - was very busy.
He said "by happenchance" two plainclothes officers were on duty, PCs Duddy and Roberts, at around 10.30am.
Mr Hopkins said PC Duddy noted McCarthy was sweating and approached and explained the search process to him.
McCarthy asked who they were and when they produced their warrant cards, he backed off towards a wall and produced a knife.
The court heard he held the black handled kitchen knife in his right hand and started shouting "do you want to fight?" to court security.
When he started moving forwards and held the knife aloft, the officers approached from behind and "manhandled him to the floor".
Mr Hopkins said: "They were in plainclothes and not wearing body armour and acted in the Crown's submission very courageously in taking the knife from the defendant."
McCarthy, whose convictions for offences including being drunk and disorderly date back to 2008, was convicted of possessing a knife in public in January 2013.
He was jailed for carrying blades in public in November 2013 and February 2014, on the second occasion when he was also convicted of having an offensive weapon.
In October 2014, he was locked up for two years and eight months for arson and possession of a knife, after drunkenly setting fire to his room at a house in Tuebrook .
He caused "immense damage" to the property, but said he was extremely drunk, angry and sick of others in the house leaving hypodermic needles everywhere .
McCarthy was later jailed for three years and four months for four counts of possession of knives in public, then jailed again for threats made outside a police station.
Mr Lawrenson said: "He is a man who wishes to go back to prison. Obviously your honour will oblige - there is no other sentence that can be imposed today in any event.
"He had only been released from prison a few days prior... he was homeless on release, sleeping rough. Thankfully nobody was hurt.
"Sadly he is becoming or has actually become institutionalised. He's simply unable to cope outside of prison.
"One thing he does wish me to say is he wishes me to apologise if he caused upset on that day."
Mr Lawrenson said his client's demeanour was usually completely different and he was "polite and lucid".
Judge Anil Murray said the two police officers acted with "substantial courage" to stop McCarthy and grab the knife.
He said: "This was a very serious offence. You deliberately bought the knife and brought it to this court.
"Having a knife whilst drunk and having it in a place where staff are very alert could have led to very serious consequences."
The judge jailed McCarthy for two and a half years, who smiled on a video link from HMP Liverpool.
