Clamping companies are acting illegally by imposing an exorbitant charge for releasing cars that have been clamped or towed away, claim the RAC Foundation.

And although the courts have upheld the right to clamp and charge a reasonable fee for release, even that is on shaky legal grounds says Dr Chris Elliott in a review of the law relating to parking.

He argues that clamping a vehicle left on private land where no parking is allowed is too often used to punish motorists - yet the principle of one individual punishing another is not one sanctioned by the law.

The director of the RAC Foundation Professor Stephen Glaister is now urging the Government to carry out a fundamental review of the law.