UK highway bosses have had to call in a European debt recovery agency to chase nearly 19,000 overseas drivers who have failed to pay in the first month of a new river crossing charging scheme.

The 18,716 overseas cases are part of a total non-payment figure of 130,306 at the Dartford River Crossing on the M25 to the east of London.

The cases relate to the month of December and follow the November 30 scrapping of toll booths at the crossing in favour of paying online, by phone or by account.

Of the 130,306 road users sent penalty charge notices during December, a total of 73,898 have been settled. The Highways Agency said more than 90% of the journeys at the crossing during December have now been paid.

RAC Foundation director Professor Stephen Glaister said: " There are a significant number of foreign drivers trying to avoid the charge. It will be interesting to see what success rate the debt collection agency achieves chasing hauliers and motorists once they leave these shores.

"And once again, it begs the question: why can't people be made to pay at the ports before they depart the UK?"

AA president Edmund King said: "It's unsurprising that the number of foreign drivers dodging the charge is significantly greater - around double - the original estimate of 14%, reflecting a general lack of payment facilities at relevant motorway service areas and ports for outbound cross-Channel drivers.

"However, many more British drivers are not paying too, which may also highlight the need for improved signage around the crossing, as well as better payment facilities."