Johns was born on 1 September 1951.[3] He was educated at Newquay Grammar School in Cornwall and then Imperial College London, where he studied physics.[4]
Naval career
Johns joined the Royal Navy in 1973. On 1 September 1975, he was promoted to lieutenant, with seniority from 1 January 1975.[5] After his initial postings, Johns trained as a helicopter pilot and then served as a Westland Sea King pilot with 824 Naval Air Squadron aboard HMS Ark Royal. He became a flying instructor in 1979. In 1981, he was given his first command on board HMS Yarnton in Hong Kong and was promoted to lieutenant commander on 16 October 1982.[6] After holding other naval posts, he was promoted to commander on 30 June 1988[7] and then commanded the frigatesHMS Juno and HMS Ariadne between 1988 and 1990.[8]
Johns attained the rank of captain on 31 December 1994.[9] Between various appointments at the Ministry of Defence, he held the command of the frigate HMS Campbeltown from 1995 to 1996.[8]