The idea that in the 21st century a European prince can write a personal letter to another royal family, and call a halt to a hugely expensive urban development, is both fantastic and faintly reassuring. In this electronic and essentially republican age, it suggests that the art of letter-writing is not dead, that personal connections matter and that the monarchy is more than mere decoration.

Prince Charles, heir to the British throne, is a long-standing critic of modernist architecture. He objects to the idea of a gleaming glass-and-copper complex on the fringes of London’s genteel Chelsea, overlooking Sir Christopher Wren’s Royal Hospital. So he wrote to the Qatari royal family, whose formidable resources are financing the project, to say so.