A dispute with the US Embassy in London over payment of the London Congestion Charge escalated on 27 March 2006 when Livingstone criticised the Embassy's decision not to pay. The Embassy argued that the charge is a form of taxation, not a charge for a service, and diplomats and their staff are therefore exempt under the 1961 Vienna Convention on Diplomatic Relations. Embassy officials have never paid the charge, which was instituted in 2003. Livingstone, however, alleged that the decision was made by Robert Tuttle, who took up the post of Ambassador in July 2005. Livingstone described Tuttle as "one of George Bush's closest cronies and a big funder of his election campaign" and said he was trying to "skive out of [paying] like some chiselling little crook". The group Liberty and Law reported this remark to the Standards Board for England as a breach of its code, but the board chose not to investigate it.