The Driving and Vehicle Licensing Agency (DVLA) has raised more than 9 million since 2002 by selling motorists' personal details to private wheel-clamping and car parking firms.
The DVLA charges 2.50 a time, or a flat fee of 3000 a year, to provide organisations with the personal records of any motorist caught parking too long on private property.
In 2007, the income reached a new high, with the DVLA raising 3.7m by selling the names and addresses of more than 1.3 million registered vehicle keepers to private firms.
Mike Hancock, MP for Portsmouth South, said: 'I think the figures are outrageous. I don't think they should be allowed to sell people's personal details and I think the Government should step in now to stop it. It is an utter disgrace.'
The DVLA responded, saying the release of information does not contravene the Data Protection Act, and pointed out that it had a legal responsibility to provide the information to anyone who had 'reasonable cause' to need it.
A spokesman said: 'The DVLA makes no profit from providing this information to parking companies. The Agency charges an administration fee to cover the costs of providing the information - if it did not the cost would fall to the taxpayer.'