The number of private parking firms issuing tickets to drivers has increased by nearly two-thirds in just five years.
New figures from the RAC Foundation found 159 companies obtained records from the Driver and Vehicle Licensing Agency (DVLA) to chase car owners for alleged infringements in private car parks between April and June.
That is up 64% from 97 during the same period in 2016.
The government statistics show private parking firms issued 1.95 million tickets to drivers on sites such as shopping centres, leisure facilities and motorway service areas.
If that rate continues for the rest of the financial year the total would come close to the record high of 8.4 million set in 2019/20.
Tickets can cost drivers as much as £100.
The implementation of a government-sanctioned code of practice, a single appeals service, and a system of charges and penalties that would be more in line with those levied by councils is awaiting ministerial sign-off.
Philip Boynes, chief executive of Britain's biggest parking firm, PrivateEye, told MPs on the housing, communities and local government select committee last week that the "average profit of a car parking operator was about 2.1%".
But RAC Foundation director Steve Gooding said the DVLA's figures "cast doubt on the industry view shared with the committee that margins are hanging by a hairsbreadth".
"If that's the case then how come more and more appear to be joining the industry that is already on track this year to issue a near-record level of demands for parking charges?
"It is inconceivable that more than eight million drivers are setting out each year consciously deciding to flout parking rules and risk ending up with a parking charge.
"These numbers, which have risen in leaps and bounds over the last 10 years, suggest we have a system that isn't working - not for the motorists who are receiving charge demands and not for the private landowners either."