The 1954 Walt Disney film of Jules Verne’s novel remains a classic. Your wind-up metal model, made from the 1950s to the 70s, should include the original key that came in an envelope. If it’s in good condition, the original stickers are intact and the mechanism works, you could be looking at more than £200. The sub belonged to Captain Nemo as he searched for the lost city of Atlantis. There are several models and toys, including some limited editions.