
Oh, the difficulties of mastering the fine details that go hand in hand with the job of being British prime minister.
Consider the protocol for greeting visitors at 10 Downing Street. Or Number 10 as it's known here -- the official residence and offices of the prime minister.
David Cameron moved into Number 10 just last week. There are still vans delivering furniture.
Today, he welcomed his first foreign leader, Canada's Stephen Harper.
As Harper's motorcade pulled up outside the black brick building, Cameron strode through the front door and down the drive to greet him.
The two leaders shook hands.
"Very good to see you," said the British PM.
"Welcome."
The two leaders then paused and turned to the media hordes for the obligatory photos.
"By the door," bellowed a print photographer. "Over by the door."
A sheepish Cameron followed orders.
He and Harper moved 10 metres down the drive to stand in front of the black door with its centre knob and white number "10"
"It's his first time," said the photographer. "He'll get used to it."
No doubt.