Wheel-clampers have been outlawed from clamping vehicles on private land under new legislation in England and Wales.
The Protection of Freedoms Act makes it an offence to clamp on private land.
The law does not affect Northern Ireland, and clamping and towing away on private land has been banned in Scotland since 1992.
But landowners are boosted by stronger laws on ticketing, which mean unpaid charges can be claimed from the keeper of the vehicle, as well as the driver.
And the government has also agreed on an independent appeals service funded by the British Parking Association (BPA).
This will allow motorists to appeal against a parking charge issued on private land by a company that is a member of the BPA's approved operator scheme.
Lord Taylor of Holbeach, the Home Office minister responsible for changes to vehicle clamping law, said: "This common-sense ban will give motorists the protection they deserve against rogue wheel-clamping and towing companies.
"It will save motorists £55m each year in clamping charges and finally penalise the real criminals - the corrupt firms themselves."
Local Transport Minister Norman Baker said: "These new parking arrangements deliver a fairer legal framework for motorists and landowners, while getting rid of the indiscriminate clamping and towing by private companies for good."
But the AA and the BPA have both said the new measures do not go far enough, expressing concern over a lack of protection from rogue parking operators.
A BPA spokesman also said there may be continuing issues for motorists because of little known by-laws giving landowners the right to manage their parking in any way they choose. These include some car parks at railway stations, airports and port authorities.
And the AA has concerns that rogue operators may begin issuing bogus parking tickets on private land.
BPA chief executive Patrick Troy said: "The Protection of Freedoms Act ushers in perhaps the most significant shake-up of the private parking industry ever seen in this country and there is much that we and the government can be proud of.
"However, the regulations do not yet go far enough. An independent appeals service which is not binding on all operators is likely to be a recipe for confusion among motorists and a ban on clamping is no substitute for proper regulation of the industry.
"That being said, the new appeals service, such as it is, will provide a long-overdue layer of protection for motorists who want to know that they no longer have to look to the courts for recourse when they feel that a parking enforcement notice has been unfairly issued."