M.I. High is a British action television series produced by Kudos for CBBC and created by Keith Brumpton. The series focuses on a team of undercover teenage spies working for a fictional version of the secret intelligence agency MI9 who have to balance their school life with their jobs as secret agents. The line-up of spies has altered between the show's seven series. The series premiered on 8 January 2007 and originally ended on 21 March 2011 after five series, before being revived for a further two series that were broadcast between 7 January 2013 and 31 March 2014. The show was cancelled in 2015, as the main filming locations of the series no longer existed. Premise The series follows the adventures of four secondary school pupils who work as undercover spies. The spies are led by MI9 agent Frank London (Jonny Freeman) whose cover job is a school caretaker. All other spies' covers have been blown, and the only spies left undercover are those still being trained, including those still enrolled in school. To reach their base 230 feet below the school, they slide a light switch across which reveals a fingerprint scanner lock. They enter the caretaker's store room and pull a broom which turns the floor into a high-speed lift which changes the spies' clothing and hairstyles. The identity of the overarching villains The Grand Master (Series 1–5) and The Mastermind (Series 6–7) remains a mystery within the show. The team must constantly save the world from domination by a variety of villains, whilst hiding their spy identities from their teachers and peers, and completing their school work. Production Writing Series producer Kerry Appleyard revealed that the concept for the show came from the creator and writer of the show Keith Brumpton who had the idea it would be fun to do a kids spy show and worked on the concept that kids find it very hard to keep secrets. MI5 and MI6 did not want the production team to use their names in the television programme but did allow them to use the name of the now defunct MI9 which back in World War II was in charge of covert operations in the UK and overseas and created various gadgets. Producer Kerry Appleyard thought that it was appropriate because the show has a lot of fantastic gadgets. Casting Series 1 When the auditions were held for