There will be no change in the US Embassy's stance against paying the congestion charge in London, it has been revealed.
Despite a change in ambassador, the US State Department said there would be no U-turn on the issue.
As of June 3, the embassy owed Transport for London (TfL) nearly £3.5m in congestion charge fines.
The US Embassy has refused to pay, claiming the levy is a tax and therefore its diplomats are immune.
Louis Susman was sworn in as new US ambassador in London two weeks ago.
But despite the new administration's perceived greener stance, and recent overtures to environmental campaigners in the capital by embassy officials, Washington has ruled that the penalties will continue to be ignored.
"There has been no change in policy regarding the congestion tax," said a spokesman for the US Department of State.
"This is a long standing US policy and is not changed by the change in ambassador."
He added: "We believe the charge to be a tax that is prohibited by various treaties."
The embassy has staged a series of special screenings of environmental films, including one by Hollywood actor Leonardo DiCaprio, to which members of London's green movement have been invited.
"We have been invited to the embassy to watch a series of films and it is nice they have opened up," said Sian Berry, former Mayoral candidate for the Green Party.
"But on this issue they are not moving. It is a double standard when one part of the embassy is doing one thing and another department doing another."