5 football transfers that shocked the world

2. Mo Johnston - Nantes to Rangers, 1989 (£1.9 million)

Mo Johnston's move to Ranger is as historic as it was shocking at the time

This transfer is not shocking due to the transfer fees or the star power involved, but rather the cultural significance. A former Celtic player, Mo Johnston made over 100 appearances for the club before moving to Nantes in 1987. Two years later, he declined a move back to his old club and opted to join their biggest rivals Rangers instead.

Celtic vs Rangers (the Old Firm Derby) is one of the biggest rivalries in the world. The Celtic support largely comprises of Catholics, whereas the Rangers fans are primarily Protestant Christians. Johnston was an openly Catholic man who chose to join the Rangers - this decision made him the first-ever high-profile Catholic signing to play for the club since World War 1, as well as only the second player to cross the Old Firm Divide.

From the early 20th century onwards, Catholics had not been knowingly signed by Rangers, nor employed in other prominent roles as an 'unwritten rule' which the club followed. After Johnstone's signing, loyal Protestants vowed never to return to Ibrox, and staunch Catholics burnt effigies of Mo for promising to re-sign for them (from Nantes) before spurning his old club at the 11th hour for their deadly rivals.

The Scottish international would score a late winner for Rangers in the Old Firm Derby, which softened the Protestants' attitude towards their star striker. Since Johnston's signing, an influx of overseas footballers have contributed to Catholic players becoming commonplace at Rangers. In hindsight, what the striker did was not only brave, but it set a precedent going forward and has changed the rivalry.