Nearly 19,000 overseas drivers failed to pay in the first month that the Dartford crossing operated its cash-free charging scheme.
The Highways Agency is looking at appointed an international debt recovery agency to reclaim what is owed.
The toll for the Dartford crossings are now operated in the same way as the Congestion Charge – with a website and phoneline to make payments based on reg plate recognition. It is the same scheme as is proposed for the various east London crossings planned for the next decade.
The 18,716 overseas non-payers are a proportion of the 130,306 who failed to pay in December after the new routine was established on November 30. Of those 73,898 have now been settled and more than 90% overall paid up.