Ken Livingstone could take the US embassy to court in America to retrieve £375,000 in unpaid congestion charge fines. Transport for London (TfL), the Mayor of London’s transport body, is taking legal advice about pursuing the embassy in the US courts for charges outstanding since its diplomats stopped paying in July last year. Diplomatic immunity prevents any action in a British court. Foreign embassies account for £3.6m in unpaid congestion fines. They claim the Vienna convention exempts them.