Who is Jude Scanlon from Jellicoe Road and what is their importance?

Jude Scanlon, Brigadier of the Cadets, has an office at the school. He and Hannah grew up together, and they even had a relationship, which was destroyed by the unwillingness by their unwillingness to accept that they were the only two surviving members of their friends. Jude stops Taylor from going to Sydney, and he later becomes Taylor and Jessa's guardian.