Three teams in the history of the tournament were at the top of the rankings on Christmas, but they found themselves in the ranks after being deprived of automatic promotion. Every time this happened, all three could not be promoted.
Ipswitch Town were top of the game on 49 points in the 2004-5 season, but ended in sixth and then lost to West Ham in the semi-finals.
Watford was top of 43 points from 2007-08 but ended in sixth – and ended in the semi-finals, this time to the ultimate winner of Hull.
Recently, Leeds were top of the top of 48 points from 2018-19, before finishing third, but then lost to the derby in the semi-finals.
What does it mean for this season? Sheffield United was at the top of Christmas last year before quitting two key players – but after Bristol City beat him last week, at least look at him to reach the final.