A rogue trader who threatened business owners if they refused to meet his vast demands for the cost of laying tarmac has been jailed for 15 months.

Joseph Kennedy, who sometimes claimed he was working for the local council or the Highways Agency, would "cold call" on his unsuspecting victims and charge inflated sums for laying tarmac.

Prosecuting, Tom Storey did not formally open the case at Teesside Crown Court, but said that Kennedy had threatened to f***k one man's wife and challenged his 17-year-old step son to a fight when they disputed the work.

Another unnamed victim thought he was going to get a "good hiding", while Anne Richards, the owner of the Little Bistro caf on the A1 near Leeming, North Yorkshire, whose complaint sparked the investigation, also described how she felt threatened by Kennedy.

A previous court hearing had heard how Mrs Richards signed for 30 loads of tarmac, but balked at his demands for between £11,000 and £15,000.

In another incident the owners of three factory units in Coventry agreed a £400 payment only to be billed for £2,400.

When people did not pay his threats included informing businesses that he was a traveller and that he could move caravans onto their premises to shut them down until they paid.

Kennedy, 40, of the Sutton Road caravan site, in Doncaster, South Yorkshire, pleaded guilty to four blackmail offences between February and October 2004 and one of making a false statement under the Trade Descriptions Act.

The father of three, who produced a number of character witnesses, was said to suffer from a heart murmur, while his wife, Mary had a spine condition which meant she had to walk with a stick.

His defence counsel Nigel Edwards said he was the principal bread winner and primary carer for his wife and children.

He said Kennedy was a very loud, forthright individual and claimed this could be misinterpreted as him being aggressive.

The defendant had undertaken some 160 jobs during the course of his business - including work for the BBC in Leeds which was said to be of sufficient quality and for which he was paid more than £23,000.

Mr Edwards said: "He is not a door knocker or an individual who seeks jobs from little old ladies - all the work is for commercial businesses.

"He may have chanced his arm in terms of the amount of money he was seeking from some of the complainants, but disputes the fact that menaces might have been used and is clear that no violence was perpetrated."

Judge Peter Armstrong jailed Kennedy for a total of 15 months, stating that he would be automatically released half way through his sentence.

The judge said: "Blackmail is a very serious offence and I hope your spell in custody will deter others from thinking this is an appropriate way of going about business."

Trading standards officer Ruth Taylor, who was commended by the judge for her thoroughness in investigating Kennedy, said: "The message is very strong - the courts will not tolerate this type of behaviour and neither will North Yorkshire Trading Standards."

Miss Taylor said there were other victims of Kennedy, but in some instances they were too scared to give statements or come to co

urt. Kennedy's offending stretched from North Yorkshire, to West Yorkshire, Derbyshire and the West Midlands.

Four further blackmail offences and three of breaching the Trade Descriptions Act, which were denied, were allowed to be left on file.

Two cars, a £125,000 Bentley and a £60,000 Mercedes, which were seized from him, form part of proceeds of crime proceedings against Kennedy which could confiscate the profits he made.

The court heard these had been delayed with Judge Armstrong allowing more time for investigations to take place.