John Liffen is Curator of Communications and Electricity Supply at the Science Museum, London, a post to which he was appointed in 2004. He has worked on a number of exhibitions, including ‘Making the Modern World’ (2000), ‘Dan Dare and the Birth of High-Tech Britain’ (2008) and most recently ‘Information Age’ (2014), the major new communications gallery. He has lectured and published many papers and articles on telecommunications history and on early railways. He also contributed a chapter in Science for the Nation, the Science Museum’s centenary history (2010). He has written ScM blogposts on spark wireless telegraphy and Cooke and Wheatstone’s five-needle telegraph.