Trevor Dannatt's splendid work on the Royal Naval College and the Dreadnought Museum at Greenwich, for the University of Greenwich, has rightly received lavish praise. Visiting the revitalised buildings, I hear a curious story about the Painted Hall, where Christopher Wren was advised that the structure he had designed would not stand, and needed two additional columns. The Great Mathematician acquiesced and the columns were installed. Later on, it emerged that they were three inches short of the beam they were supposed to support. Designer's joke? Specialist sub-contractor's botch? Who knows; nothing fell down.