The details of more than 19,000 vehicles are allegedly being bought from the DVLA every day by parking firms chasing unpaid fines.
MPs have been told that between April and June the DVLA sold 1.74million vehicle keeper records, up from 1.06million in the same period last year.
The DVLA, which sells the information for £2.50 a vehicle, is generating almost £1.5million a month.
But MPs have warned some ‘bully boy’ firms are using the information to hound innocent motorists, and called for a crackdown to protect drivers after it was revealed the trade in information had reached record levels.
The RAC Foundation claimed the industry was out of control, with the data suggesting a parking fine was issued every four and half seconds.
And it said details of around seven million vehicles could be sold during the financial year, suggesting almost a quarter of motorists were being chased for a parking fine.
Tory MP Sir Greg Knight, who has tabled a private members’ Bill in the Commons to crack down on the self-regulated parking industry, said: “These figures are concerning. It is highly unlikely there has been a massive increase in bad parking.
“Instead, bully-boy parking firms are hounding innocent motorists and milking them for money.
“We need to put rogue firms out of business. There are many private parking companies who are playing fair.
“But others are clearly making a killing out of pursuing and persecuting motorists who have done nothing wrong.”
Fellow Tory Jacob Rees-Mogg added: “My concern is that some of these firms use the fines they levy as part of their business model.
“This gives them a strong incentive to levy fines unjustly and aggressively.
“We would not need a new law if DVLA was more willing to strike off companies suspected of behaving badly.”
MPs fear the information is being widely misused, with motorists unfairly targeted while visiting hospitals and high street shops.
Drivers have complained about being fined up to £100 for returning to their cars a few minutes late, or after being unable to buy a ticket because of a faulty machine.
ParkingEye, owned by outsourcing firm Capita, is one of the most prolific parking firms to seek information, obtaining 570,000 vehicle records in the three-month period, followed by Smart Parking with 125,000 and Euro Car Parks with 118,000.
A spokesman for the DVLA, based in Morriston , said: “We take our responsibility to protect information extremely seriously and we have robust safeguards in place to ensure data is used correctly.
“Our data release charges are set to recover the cost of providing the information.”