'Nonsense!' said the official from the Admiralty. Sir Walter got up and left the room while we looked blankly at the table. He came back in ten minutes with a long face. 'I have spoken to Alloa,' he said. 'Had him out of bed—very grumpy. He went straight home after Mulross's dinner.'
I can only assume that this book may have inspired Agatha Christie's spy thrillers. It certainly would explain the unexplainable - that is, The Big Four and Passenger to Frankfurt.