Another example is the popular Belgian comic series concerning the adventures of MI5 agent Colonel Clifton. Clifton once featured in a story entitled "Jade", published in 2003. In it he meets two characters called Blake and Mortimer, though even as caricatures they bear little resemblance (perhaps deliberately) to Jacob's originals. The story includes elements from the original books, such as the entrance to the secret passage from "S.O.S. Météores" and the cave that doubles as a submarine base in "L'Affaire Francis Blake".