Unpaid tickets at the Dartford Crossing have boomed by around 160 per cent in the last three years.
Freedom of information figures given to the BBC reveal the number of drivers unable to pay the toll has risen from 15,216 in 2010 to 39,996 last year.
The toll costs £2 each way for car-drivers and £2.50 for two-axle goods vehicles.
When a motorist arrives at the crossing with insufficient cash, they are issued a Dartford Thurrock Debt (DTD) ticket, which allows them to continue on their journey.
The motorist has seven days to pay the charge and then the business administration team will send a reminder.
The number of DTD tickets left unpaid within this time period also doubled from 639 in 2010 to 1336 last year.
However the forms are not issued to commercial vehicles which are instead refused permission and turned around.
A Highways Agency spokesman said: "The figures speak for themselves and with significantly less than one per cent of people currently failing to pay to use the Dartford Crossing this has proved not to be a major issue.
"When Dart Charge is introduced, from October, new legislation will enable us to effectively address non-compliance.
"We are serious about tackling cases of evasion and we will use effective penalty and recovery processes that have been proven elsewhere."
The number of people who have failed to pay to use the Dartford Crossing between September 2009 and January 2014 totalled 5,309.
Dartford MP Gareth Johnson said: “The number of people avoiding the tolls remains a very small amount, I understand it’s 1 in every 42 000 journeys but the Department of Transport must do all it can to pursue any deliberate non-payment.
“Commercial vehicles, foreign lorries and anyone unable to prove their Identity are refused passage if they don’t have sufficient money.
“We have brought in measures that give power to seize vehicles of those who don’t pay and these powers come into effect with the free flow tolling system in October.”