Councils across the UK have written off thousands of parking tickets worth millions of pounds in the last two years as they could not trace the drivers of the foreign-registered vehicles involved.
Altogether 20 councils and police forces in the UK with passenger and freight ferry terminals, ports and other major transport hubs near or in their areas responded to freedom of information requests.
Areas losing most potential revenue included London, Portsmouth, Newcastle and Edinburgh.
Westminster City Council said that between July 2007 and October this year, 45,437 tickets worth 3.08m were written off as drivers of foreign-registered vehicles could not be traced – and 3.2m is still owed.
Lee Rowley, the council's cabinet member for parking, said: "British taxpayers can no longer foot the bill for foreign motorists who seem to think the rules of this country do not apply to them.
"We would like to see a more rigorous system put in place to hold these drivers to account and send a clear message that this blatant disregard of the law will not be tolerated."
Portsmouth City Council said between April 2008 and October 31 this year, they wrote off parking fines of 110,965 for foreign-registered vehicles.
The council said: "On the expiry of a penalty charge notice (28 days) the DVLA will advise registered keeper details and if they are overseas and outside Portsmouth City Council jurisdiction, then Portsmouth City Council cancels or writes off the amount."
Newcastle City Council admitted writing of unpaid tickets worth 84,470 between April 2008 and December 6 this year.
Other councils said they either did not hold the details or a search of their records would exceed limits under freedom of information requests.
Edinburgh City Council said parking tickets to foreign-registered vehicles worth 233,993.70 were written off during the 2008/09 financial year.
They also said 211,051 in parking tickets issued to foreign-registered vehicles was written off between April 2009 and October 1 this year as drivers could not be traced and tickets were not paid.