A cashless parking scheme in central London was partially down for two hours during rush hour traffic.
The pay-by-phone system was introduced almost a year ago
Motorists trying to park in Westminster were unable to use the pay-by-phone system introduced almost a year ago because of a fault.
Parking meters in the area have been scrapped in favour of the scheme whereby drivers pay by sending their details via a text or call.
The council said drivers were still able to pay via text message.
Since the scheme was introduced, 2,000 parking meters have been removed from the area.
The remaining 2,000 are expected to be removed by the end of March.
Pete Donovan, who owns a fire protection business in the city, said two of his engineers in central London were trying to find a parking space.
"It's hard enough as it is trying to do the job without obstructions like this put in front of you.
"I understand we're trying to move towards a cashless society but unless the system works there's no point in having it."
A spokeswoman for Westminster Council said: "Parking attendants were alerted straight away so there was no ticketing."
"We advised customers to use nearby pay-and-display machines."