TfL, the local authority in charge of most of London's transport network, says it is owed millions in unpaid congestion fee charges from countries around the world.
The top "culprit" is the US embassy which currently owes more than £14 million in charges which have remained unpaid since 2003, when the charge was first introduced.
Despite reminders, the "stubborn" embassies are refusing to pay what they owe and TfL wants the matter taken up at the International Court of Justice.
A charge not a tax, so diplomats not exempt
"We and the UK Government are clear that the Congestion Charge is a charge for a service and not a tax. This means that diplomats are not exempt from paying it," TfL said in a statement.
"We will continue to pursue all unpaid Congestion Charge fees and related penalty charge notices."
London's authorities have had trouble with parking fines in the past, with diplomats arguing they are exempt from charges because, for example, a parking ticket is a fine or a tax, which they are not obliged to pay.
TfL is determined to recover its cash, arguing the payment is for a "charge" not a "tax".
Big embassies, big debts
Second in the league of big collectors of debt, but not big spenders when it comes to paying out, is Japan, with its diplomats owing more than £10 million (€11.7 million) in fees. After Japan comes India's High Commission, which owes £8.6 million (€10 million), followed by Nigeria at £8.4 million (€9.8 million) and China trailing a little at £7.9 million (€9.2 million).
Togo's diplomats appear to have been much more more generous in the settlement of their fees. Their outstanding debt is just £40 (€47).
The total amount of money owed to TfL by foreign embassies and high commissions is some £143 million (€167 million), according to TfL's own reckoning.
