David Liddle was born in Yorkshire, England, in 1952. He received the B.Sc.(Eng.) degree in aeronautical engineering from the Imperial College of Science and Technology, London, England. He further received at that time his Associateship of the City and Guilds (London) Institute, London, England.In 1974 he joined Slingsby Engineering Limited (SEL), Kirkbymoorside, York, England, where he has worked as Senior Design Engineer and Project Manager on the development of a number of manned and remotely operated underwater vehicles. He is currently employed as Marketing Manager with SEL and has been closely involved in the evolution of the latest TROJAN vehicle.