The huge amounts taken from drivers in private car parks has reached "epidemic" levels, the AA said today.
Private parking enforcement was "out of control" with "bad and immoral" wheelclamping practices, the AA added.
The scale and level of punishment meted out by an army of private enforcers was "frightening and often bordering on criminality", the motoring organisation added.
The AA cited the following recent examples:
* An elderly pensioner and her sick husband who were wrongly double-charged £370 by a clamper/tower who belonged to the "trade association" and breached its code despite having declared it would abide by its rules. They have now recovered their cash after threats of legal action;
* A woman who stopped, literally, for seconds, and heard a noise at the rear of her car. Someone said "I won't be a moment" and clamped her car while she sat in it with the engine running before charging her £300;
* A woman who was given a ticket in a free car park for straddling lines. The ticket could not be paid as there were no details on it, and then she was sent a "£100 charge certificate" after the parking firm obtained her details from the Driver and Vehicle Licensing Agency (DVLA) despite inadequate signing in the car park;
* A woman, on her own, whose car was clamped and removed in Enfield, north London, at night and was charged £527 to get her car back.
The AA said the lure of uncontrolled money-raking is so great that some companies offer DIY packs, with signs that can be printed off the internet.
It added that anyone could now set themselves up as a parking enforcer and "start to cash in". The companies, who use their access to DVLA drivers' records, send out parking tickets on behalf of the DIY enforcers and take a cut of the fines.
The AA's public affairs head Paul Watters said: "Self-regulation is not working as there are too many firms and individuals operating in this often shady area. The trade body members making and enforcing the rules are trying to rein in something that is spiralling out of control.
"Private parking enforcement is big business, generating millions of pounds and no-one notices and acts when the rules are broken. The public have absolutely no protection if a private parking firm acts unfairly - it is a civil matter and no-one is interested in helping. How on earth can people believe that if you appeal to an enforcer you are going to get a fair hearing? The BPA (British Parking Association) will not act as arbiter."
He went on: "It is time for regulation of private enforcement through local authorities who can licence the land where parking is to be controlled.
"We we need a completely independent appeal system, perhaps through the parking adjudication services which already exist."
A Home Office spokesman said: "The Government's public consultation into wheelclamping proposed the introduction of compulsory licensing of vehicle immobilisation businesses to tackle the main areas of complaint.
"These include companies issuing excessive penalties for releasing clamped cars and towed cars, inadequate signs warning drivers that clamping takes place and lack of effective appeals processes.
"That consultation has now ended and we are considering the responses. We will publish the findings later in the year."
Home Office Minister Lord West said: "There are clearly some wheelclamping businesses that indulge in unacceptable behaviour including unclear signage and excessive fees.
"The Government is currently working hard to bring in legislation to prevent abuses by these firms and their employees.
"Proposals are for the introduction of compulsory licensing for all wheelclamping businesses including those whose practices include excessive fines for releasing clamped cars, towing cars unreasonably quickly after being clamped and putting up hidden, missing or confusing signs warning drivers that clamping takes place.
"Public consultation on these proposals has already ended. The next stage is to draft legislation and we hope to introduce tough new regulations next year."Reuse content