It could be many months before motorists are fully protected against cowboy wheelclampers despite recently-introduced legislation, according to the RAC Foundation.
The establishment of an appeals panel for those wrongly penalised on private land was a key part of the Crime and Security Bill which became an Act in April this year.
But the RAC Foundation said it understood such a panel was unlikely to become reality before 2012 at the earliest.
Even then it will not cover drivers who have been targeted by the increasing number of companies which are turning to the use of tickets.
The foundation said a limited appeals service was currently being set up by the British Parking Association (BPA) which represents parking companies.
Initially the scheme will include only a small number of its members. If the pilot is successful it will be extended to all members later next year. However not all parking companies have BPA membership.
RAC Foundation director Professor Stephen Glaister said: "This will be a huge disappointment to frustrated motorists ripped off by unscrupulous parking enforcers.
"The nation's 34 million drivers were led to believe an independent appeals service would follow hot on the heels of the legislation.
"But even when such a service is established it will only cover clampers and not the increasing number of companies which are issuing tickets instead."
He went on: "We want the Government to provide an appeals service, a code of practice and a company registration scheme which cover all parking enforcement firms operating on private land. Why is this so difficult to do?
"We need urgent clarification from ministers as to how and when they are going to finally sort out this mess and make good the promises made to drivers. If action is to be taken more quickly than we understand, then great. But please let us know."
A Home Office spokesman said: "The Government is committed to tackling the menace of rogue private sector wheelclampers and is looking at all the available options."