Five members of a car clamping operation which used motorists "as a licence to print money" have been jailed for a total of almost eight years.
Andrew Minshull, Debbie Worton, Simon Barry, Christopher Cartwright and Faisal Qadeer remained impassive in the dock at Worcester Crown Court as Judge John Cavell condemned them for "milking" the public out of up to £500,000.
Passing custodial sentences ranging between 12 and 32 months, Judge Cavell said Minshull's firm, Redditch-based Midland Parking Contracts, had frequently targeted and exploited vulnerable members of society.
Minshull, described by the judge as the "main man" at the rogue firm, was jailed for 32 months, while his ex-partner, Debbie Worton - the "public face of the company" - was sentenced to 12 months.
Barry, who took part in clamping and also liaised with landowners, was given a 21-month jail term, while both Cartwright and Qadeer, who selected victims in their roles as frontline operatives, were jailed for 15 months.
Minshull, 38, of Hatfield Close, Redditch; Worton, 43, of Longdon Close, Redditch; Barry, 38, of Lilac Close, Evesham; Cartwright, 31, of Salisbury Drive, Kidderminster; and Qadeer, 35, of Mount Pleasant, Redditch, all pleaded guilty to conspiracy to defraud in January.
Describing Midlands Parking Contracts' treatment of drivers between 2006 and 2009 as disgraceful, Judge Cavell told the defendants: "It is of course something that most people accept that illegal parking can cause very real problems to traders and other people and there can be no reasonable objection to the control of illegal parking by legitimate and proper enforcement.
"What of course is wholly wrong is the use of enforcement measures not to provide a service to help traders and others suffering from illegally-parked cars, but to use the company as a vehicle to obtain money dishonestly from the public by blatant abuse of authority and power.
"In my judgment that is plainly what happened in this case."
The conduct of the company's staff as they conned the public had, on occasion, been offensive and intimidating, causing an element of fear as well as distress, the judge added.
The court heard that the conspiracy may have netted up to £500,000, although Judge Cavell accepted that, if the figure was accurate, some of it may have been legitimate income.
Opening the facts of the case on Monday, prosecutor Anthony Potter outlined how Midland Parking Contracts used underhand tactics and intimidated drivers into parting with up to £335 to unclamp vehicles and "cancel" tow-trucks which had not been called out.
Money was even demanded before clamps had been applied and unlit signs were used at night.
Potter said the conspiracy's victims, including meter readers for water and power companies, a disabled woman displaying a blue badge, and an NHS worker transporting blood samples, were targeted in Redditch, Nuneaton, Evesham, Worcester, Coventry, Bromsgrove, and Cheltenham between March 2006 and August 2009.
Warning signs were either not prominent, were obscured by a company vehicle, or on at least one occasion were erected after motorists had parked.
The court also heard that Worton used an alias to fob off aggrieved drivers who complained by telephone, while appeal letters and County Court judgments were ignored by the firm, which had a postal address in Birmingham.
A sixth defendant, wheel-clamper Lloyd Isherwood, 39, of Groveley Lane, Birmingham, has also admitted conspiracy to defraud and will be sentenced at a later date.
Commenting on the case, Detective Sergeant Mark Roberts, of West Mercia Police, said: "Wheel clamping is legitimate but there are rules which need to be followed.
"Of course all drivers are going to be unhappy about having their vehicles clamped or towed, and the police do receive regular calls from angry and distressed motorists about it.
"However, the barrage of complaints we were receiving about Midland Parking Contracts prompted us to launch an investigation, and it showed the company and its employees were effectively demanding money with menaces.
"The clampers caused a great deal of distress to the motorists they targeted, many who were the most vulnerable members of our society, including the elderly and disabled."
Edmund King, the president of the Automobile Association praised the police for bringing the clampers to justice but warned drivers to still be vigilant ahead of government plans to outlaw clamping on private land in the autumn.
"The AA warns drivers that even though their era is almost over, the clampers are determined to milk every last penny they can and will continue using tactics that defy belief in a modern society."