The Princess of Wales has been photographed for the first time since she was hospitalised earlier this year. But while the picture, which shows Catherine in a car driven by her mother Carole Middleton, is splashed across the American celebrity website TMZ, it won’t be appearing in British newspapers. So why is the British press so scrupulous, so abstemious and so responsible – things they could never have been accused of in the Wild West days of the old Fleet Street – when their American cousins still shoot from the hip when it comes to publishing paparazzi pictures of the Royals?

The...