Richard Vaughan and the Covert Pluto Pipeline

My grandfather was an Air Raid Precaution officer based in London. He was one of the engineers who helped advise the government on the Pluto pipeline but was not allowed to discuss it with others due to national secrecy. Pluto was a long project, and they were sworn to secrecy. He had to go on board ships to check if it was working. He got involved before 1942. They weren't allowed to share photos or discuss anything until it was declassified.