A career criminal who has racked up around 150 convictions is back in jail less than four months after promising to go straight.

Sean Reed admitted stealing a bottle of whisky, threatening a supermarket customer with a lock knife, and assault by beating, at the Morrisons car park in Sittingbourne.

Victim Mark Bosch tried to peacefully intervene when he saw the 43-year-old being followed by a security guard.

But having asked Reed to “give up whatever he had and go on his way”, the have-a-go hero was sworn at and shoved before being punched in the face and stomach.

Prosecutor John O’Higgins told Maidstone Crown Court when Mr Bosch hit back, the blade was produced.

“Mr Bosch heard the click as it was opened out and the man verbally abused him and produced the weapon,” he said.

“There was a threat and Mr Bosch feared for his safety and began to back off. The man continued to threaten people with the knife.

“Someone shouted ‘drop the knife, don’t do it.’ The man then calmly picked up his bag and walked out of the car park.”

Reed, of Miller Close, Kemsley, was later arrested at his home.

Appearing at court via a video link with Elmley Prison, Sheppey, he admitted the offences, which happened on March 19.

Jailing the qualified carpenter for 10 months, Judge Charles Macdonald QC said of Mr Bosch: “He stepped in to assist the guard and for his pains you beat him and threatened him with a lock knife.”

The judge also said the “dominating” feature of the case was Reed’s long record of previous convictions.

The mitigation, he added, could be found in his remorse “and nothing else”.

Sara Haroon, defending, told the court Reed’s life had been turned upside down in 2009 when his wife left him for another man, taking their children.

“He lost his home and job in Ashford and he filled the gaping hole left in his life by the absence of his family with alcohol,” she said.

“Drink dominated this defendant’s actions on the day but now, in the cold light of day, he appreciates the consequences of his behaviour and apologises.”