VIOLENT drug dealer Jon Patterson beat up one of his customers and then photographed him as he lay cowering on the ground, a court heard today.

Patterson, 30, also attacked a passer-by in Cirencester, hitting him in the face with a crutch for no reason at all, Gloucester crown court was told.

Judge Jamie Tabor QC jailed Patterson, of Drift Way, Cirencester, for a total of four years and warned him that if he commits similar offences again he could be classed as a public danger and locked up indefinitely.

Patterson had been committing criminal offences of every kind "since he was a child" and today was his 30th court appearance, the judge said.

Patterson had been due to stand jury trial today on charges of blackmail, assault and being concerned in the supply of the drug mephedrone, known as MCat.

But he pleaded guilty at the last moment and was sentenced for the offences as well as for others he had admitted at an earlier hearing of assault causing actual bodily harm and possessing two offensive weapons.

Prosecutor Ian Dixey said that on 3rd Oct last year Patterson attacked 'vulnerable' drug addict Elliott Kirkby, demanding an extra £100 from him for drugs he had supplied.

"The defendant went to his house demanding money and Mr Kirkby eventually let him in," Mr Dixey said.

"Patterson grabbed him around the throat, pushing him to the floor and then got him into a corner of his lounge and head-butted him.

"He punched him and hit him with a floor sweeper, stamped on his chest and at one stage got out his mobile phone and took a photo of him as he was cowering on the floor in fear.

"Mr Kirkby surmised that the defendant took that picture to show others what he had done to him."

When Patterson was arrested scales with mephedrone on them were found at his house. Messages on his phone proved he was dealing - and the police also found the picture of Mr Kirkby.

Mr Dixey told the court that on 5th August this year at lunchtime Scotsman Arthur Crowe, who had newly arrived in Cirencester, was walking through the town with two women friends when they saw Patterson sitting on a bike in an alleyway off Trinity road.

Thinking he looked like a drug addict who could be trouble they crossed the road and walked away. But Patterson shouted after them demanding to know what they were laughing at.

Mr Crowe walked back to assure Patterson they were not laughing at him and suddenly the defendant hit him in the face with a crutch, forcing a tooth through his mouth so that he needed to have stitches inserted in hospital.

When police arrested Patterson the next day he had a six inch knife and a claw hammer on him.

Looking at Patterson's criminal record Judge Tabor said it was 'appalling' and he appeared to have committed just about every kind of crime over the years.

Joe Maloney, defending, said Patterson was now completely free of drug addiction himself but at the time of the offences was off his head on mephedrone and prescribed medication he was taking after breaking his ankle.

He had received psychiactric treatment for paranoia in prison, added Mr Maloney.