I'll never agree with a forward being the captain of any team. The CB is the most natural position to command his teammates in set piece situations and lead from the back.
If need be a standout commanding midfielder like Keane, but preferably a true leader like Rio, Vidic, Maguire, etc. Players that command the field through presence are all captain material
To be fair, at the time there were not many stand out choices:
https://en.wikipedia.org/wiki/2018_FIFA_World_Cup_squads#England
Fun fact: Phil Jones made the squad for the world cup.