Embassies in London have amassed debt worth more than £143.5m in unpaid congestion charges since the scheme was introduced in 2003.
Transport for London (TfL) said most embassies paid the charge but there remained a ‘stubborn minority’ who refused, adding that it is pushing for the matter to be taken up at the International Court of Justice.
Drivers are charged £15 a day to enter the central London congestion charge zone from 7am-6pm between Monday and Friday and from 12pm-6pm on weekends and bank holidays.
TfL has published a list of embassies that have accrued unpaid congestion charge fees and related penalty charge notices between 2003 and the end of last year.
The American Embassy owes the largest amount, at just over £14.6m, followed by the Embassy of Japan, which owes more than £10m.
TfL said: ‘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.
A spokesperson for the American 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 longstanding position is shared by many other diplomatic missions in London.’
