The US Secretary of State Hillary Clinton yesterday wished the Queen a happy birthday – eight days early.
But rather than signalling a breakdown in the "special relationship", it was, an American Embassy spokesman insisted, "a simple error".
The spokesman said: "The statement was sent out by Washington in error and we just assumed they had got it right and relayed the message."
The spokesman confirmed Mrs Clinton was aware of the gaffe but denied the Department was embarrassed by it. "This message was intended for release on 11 June, and the early release was a simple error," he said, adding that it was customary for the Ambassador to send a personal message on the Queen's official birthday in any case.
In the statement, Mrs Clinton wished the Queen a happy birthday, adding: "On this celebratory occasion, we pay tribute to the Queen's life and legacy and honour the special relationship between our two nations."
She was also careful to talk up the "special relationship", saying it "continues to provide a solid foundation as the United States and Britain work side by side to meet the challenges of the 21st century, from supporting the refocused mission in Afghanistan to promoting the global economic recovery to working for peace in the Middle East."