A law to crack down on cowboy car clampers operating on private land has come into force.
Unlicensed companies will be prosecuted under the new scheme
The change means every clamping company has to be licensed and staff must abide by a code of conduct.
Failure to get a licence, which requires going on a training course, could attract a £5,000 fine or six-month prison sentence.
Introduction of the scheme was delayed because too few people had completed a training course by the March deadline.
A rise in private clamping firms since wheel clamps were first used in the UK in 1983 meant more and more motorists were affected, said BBC News correspondent Tim Muffett.
He said drivers were paying up to £400 to have their cars released.
Now the setting up of wheel-clamping firms was restricted to those with a licence, a drop in the amount of clamping in private areas such as business parks and housing estates was expected, he said.
Speaking in the run-up to the original launch date, wheel clamper Rick Ellis, of Zonehold Ltd, said he was looking forward to the new licensing rules.
"Hopefully people won't think of us as cowboys any more because they will appreciate that we are licensed.
"Not any Joe Bloggs can go out and put a clamp on their car and demand money with menaces, which a lot of people seem to think we do."
Andy Drane, of the Security Industry Authority - which manages the private security industry - said the delay was caused by difficulties between trainers and awarding body, Edexcel.
The RAC Foundation has campaigned for 11 years for the introduction of statutory regulations to limit the "excesses" of private clamping companies.
Its executive director, Edmund King, said many clampers were just out to "fleece the motorist".
"Motorists should not park on private land but often these rogues encourage parking by leaving decoy cars or by hiding signs," he said.
The legislation to allow the licensing scheme was passed in the Security Industry Bill in 2001, and the Security Industry Authority set up in April 2003.
I was clamped in a delivery area by a busy town centre thoroughfare. I was away from my car for about 5 minutes; the clampers were waiting at the site and struck when I was out of site. When I returned, they pointed out two signs, both were on adjacent walls and some 8 feet off the ground, the font size was too small to be read unless very close. I did not notice either sign when I parked. The clampers demanded £95 to remove the clamp, which I paid. The site is owned by an adjacent shop. I telephoned the owner of the shop twice, on the first occasion he denied any knowledge, but when pressed during my second call, he admitted that he instructed the clamping company and that it was "an easy way to make a bit of extra cash at Christmas" (it was December). I contacted the local authority who said they had received other complaints about the site, but they were powerless to act. It stinks, I thought about taking the owner to small claims court and to get him some bad publicity, but like many of these things, my anger subsided and I moved on.
Mark Tutton, Warwick, Warwickshire
Come to Scotland. Clamping was ruled illegal here several years ago and I think that the same thing should happen in the rest of the UK.
The legislation is welcome. However, if the signs are clearly visible, then the clampers are justified in clamping people parking without permission.
Neil Small, Scotland
I was clamped after spending 2 minutes in my local Royal Mail depot. The clampers were hiding behind a building and pounced as soon as I entered the door. As I emerged, they were putting the clamp on but refused to stop. They were in an unmarked van and I had to pay there and then by credit card top get my car released. My letter of complaint to the clamping company got no response. Fleecing is the word.
David Harper, Harrow, Middlesex
My father was clamped in the early days of clamping. The car park looked as if it belongs to the hotel we were attending a function at, but unbeknown to use it didn't. The clamping warning signs were put up while we were in the hotel, and as soon as they had been nailed up they clamped every car there. Dad had a serious heart condition and seldom went out because he found cold wet weather difficult to manage - but that didn't stop the firm leaving him standing in the car park, after midnight, in the rain, refusing to unclamp the car without a hefty fine being paid.
Doris, Poole England
My fiancée and I had our car clamped whilst looking around a flat in High Wycombe. Having parked near the estate agent and only spending about 5 minutes in the flat we returned to find the car being lifted onto a lorry to be towed away. Apparently he had fitted the clamps for the correct amount of time and now he had to tow us away. 200 Miles from home and car less with just a mobile phone number to find the car. The police were unable to do anything. In the end had to meet the "clamper" in a McDonalds car park outside Uxbridge. He then drove me to a cash point in his truck to take out £250 before he would take me to the car. If was on a dirt track in the middle of nowhere, unlocked and unprotected. The car had been held to random. The receipt he gave me had not information other than a PO Box number and a telephone number with an answer machine on! This was a horrible experience and I hope that licensing the clampers goes some way to stopping this happening to other people. Needless to say we did not buy the flat, or decide to live in High Wycombe!
Giles Fairhead, High Wycombe
This will make no difference at all - even the legitimate companies act completely unreasonably and clamping is a way of making money for the companies. It has nothing to do with improving parking or dealing with those who park illegally.
GW, Exeter, Devon