Sadiq Khan has said that the hundreds of millions of pounds of unpaid congestion charge fines owed by embassies to Transport for London (TfL) is “beyond my pay grade”.
The capital’s mayor said that the row - which has developed over two decades - was based on a dispute over an international convention which he has no power to “renegotiate”.
Statistics published by TfL this week showed that London’s embassies had collectively accrued more than £143m in unpaid fines between the launch of the congestion charge in 2003 and the end of last year - with the US embassy alone owing £14.6m.
“That’s the cumulative effect of 21 years of some embassies thinking that the congestion charge - which is a charge you pay for a service - is a tax,” Mr Khan told the Standard on Tuesday.
“Now listen, it’s beyond my pay grade to renegotiate conventions that are discussed overseas and stuff - and their interpretation.
“What I’m hoping is that those embassies that aren’t currently paying the congestion charge will look at the example of those that are and understand that that’s the interpretation TfL are applying.”
Under the Vienna Convention on Diplomatic Relations, local taxes do not apply to foreign diplomats, providing diplomatic immunity from enforcement.
TfL said in a statement: “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.
“The majority of embassies in London do pay the charge, but there remains a stubborn minority who refuse to do so, despite our representations through diplomatic channels.”
Ken Livingstone, the mayor who introduced the congestion charge, sparked controversy in 2006 after likening the then-US ambassador to the UK, Robert Tuttle, to a “chiselling little crook” who had chosen to “skive out of” the “charge that everybody else is paying”.
Mr Livingstone’s successor, Boris Johnson, called the situation “an unbelievable scandal”, adding that he was prevented by the Geneva Convention from “slapping an Asbo on every single diplomat who fails to pay”.
But Mr Khan criticised Mr Johnson for doing “nothing” to resolve the situation during his subsequent career as Prime Minister.
He added: “We’re going to carry on speaking to the Government, but also carry on speaking to the embassies, to persuade them to pay the charge.”
TfL has said it is “pushing for the matter to be taken up at the International Court of Justice”.
Asked about this possibility, Mr Khan said he had “not seen any plans for us to bring a case to the ICJ”.
The congestion charge involves a £15 daily fee for driving within an area of central London between 07:00 and 18:00 on weekdays, and between noon and 18:00 on weekends and bank holidays.
The Foreign Office has told the BBC that it expects diplomats to pay the charge, adding that they believed that there was no legal grounds for diplomatic exemptions.
A spokesperson for the US Embassy in London said: "In accordance with international law as reflected in the 1961 Vienna Convention on Diplomatic Relations, our position is that the congestion charge is a tax from which diplomatic missions are exempt.
"Our long-standing position is shared by many other diplomatic missions in London.”
