A group of rogue wheel clampers who may have made up to half a million pounds have been sentenced to jail terms at Worcester Crown Court.

Six defendants pleaded guilty to conspiracy to defraud after the court heard they used their clamping company as a "licence to print money".

Their company, Midlands Parking Contracts (MPC), used underhand tactics and intimidated people, charging up to £355 to remove the clamps from their cars.

MPC operated at 19 sites. The court heard their victims included meter readers for water and power companies, a disabled woman displaying a blue badge and even a man visiting a mental health centre.

Warning signs at the parking sites were either not prominent or, as happened on at least one occasion, were erected after motorists had parked.

Estimating profits may have been as high as £500,000, counsel for the prosecution Anthony Potter told the court: "Different sites appear to have been 'policed' with more vigour than some other sites.

"It's difficult to put an accurate figure on the proceeds - we suggest a figure of up to £500,000 but it is very difficult to be specific."

Six defendants, including company owner Andrew Minshull and his partner Debbie Worton, pleaded guilty to conspiracy to defraud in January, but their pleas could not previously be reported due to a court order.

Guilty pleas were also entered last month by Simon Barry, Christopher Cartwright, Faisal Qadeer and Lloyd Isherwood, who worked as front-line staff for the rogue firm.

Minshull was sentenced to two years and eight months in jail, Barry to 21 months, Qadeer and Cartwright to 15 months each and Worton to 12 months. Isherwood's sentencing was adjourned for reports.

MPC's other victims included NHS worker Alison Overton who was driving a van carrying drugs, patients notes and blood specimens when she parked on waste ground at the back of a pub in Bromsgrove.

When she returned to her vehicle, the clampers had not started to immobilise the van but demanded she pay up nonetheless.

"I felt intimidated and was also aware of the inconvenience it would cause to patients if there were any delays," she said. "These people were just making money out of causing misery."

Det Sgt Mark Roberts of West Mercia Police said: "The barrage of complaints we were receiving about MPC prompted us to launch an investigation, and it showed the company and its employees were effectively demanding money with menaces."