The mayor of London, Ken Livingstone, already in trouble for comparing a reporter to a concentration camp guard, dug himself in further on Monday when he likened the American Ambassador Robert Tuttle to a “chiseling little crook” over the embassy’s continued refusal to pay traffic charges.

America has racked up $250,000 in penalties for about 550 outstanding tickets for the $14 fee, known as a “congestion charge” and introduced last year to ease central London’s traffic jams. Vehicles have their license plates photographed when they enter the central business zone and a bill is sent to the owner.

British diplomats in New York have kept out of hot water when it comes to paying municipal fees. According to the city’s Department of Finance, they owe a measly $625 in parking fees, none of which are delinquent in payment. The Republic of Indonesia owes the most, with $8,910 in parking fees.

The confrontational yet popular London mayor is famous for speaking his mind – often to his discredit. He is appealing a decision by the Standards Board of England to suspend him from office for four weeks for comparing a Jewish reporter to a “concentration camp guard” and “German war criminal.”

This time his remarks were directed at Mr. Tuttle, the former owner of a car dealership and personal friend of President Bush, as well as a former assistant to President Reagan. He was appointed ambassador to the Court of St. James in July.

American officials in London said they consider the fee a tax, which they are exempt from under the 1963 Vienna Convention on Consular Relations. London contends the fee is not a tax but a toll. Another 55 consulates and embassies, including Germany, are also refusing to pay.

The Vienna Convention’s article 49 declares that diplomats aren’t exempt from sales tax, tax on income made in the U.K., or “charges levied for specific services rendered.” Mr. Livingstone yesterday told reporters he would bring America to court, either in Britain or America.

“When British troops are putting their lives on the line for American foreign policy, it would be quite nice if they paid the congestion charge,” he said, adding later,”It would actually be quite nice if the American ambassador in Britain could pay the charge that everybody else is paying and not actually try and skive out of it like some chiseling little crook.”

A coalition of transit advocates in New York are rallying for a similar kind of fee to mitigate the city’s traffic congestion problems. Proposals were set back earlier this year when Mayor Bloomberg said he didn’t support the idea.