Cadillac 1 in London

Rules are rules, and they apply equally to everyone – including the President of the United States. Especially when he's on foreign soil.

After President Barack Obama's famous Cadillac limousine – known as The Beast – got stuck exiting the US embassy in Dublin, it was shipped across the Irish Sea to England, the next leg of the president's European road trip. Now the mayor of London is demanding Obama pay the congestion charge for his limo and the rest of his motorcade.

A notorious car nut and onetime automotive journalist, Major Boris Johnson insists that the £10 ($16) charge applies to each of the president's vehicles, and that the bill is currently being tabulated. The fees are only the latest part of an ongoing dispute between the city's transportation department and foreign missions like the American embassy, an issue that Johnson reportedly raised directly with Obama during his visit.

London insists that embassies in the British capital city owe some £51 million ($83m) in congestion charges for driving through the city during peak hours, of which the American embassy's share is estimated at £5.3 million ($8.7m). Diplomats view the fee as a tax from which they are exempt under international law.