History is very rarely the story of careful plans that go right. External events, unpredictable and random, are always there to send things off course. What if the White Ship hadn’t sunk in 1120, killing the heir to Henry I; was England doomed anyway to civil war and the Anarchy? What if Archduke Franz Ferdinand had taken a different route through Sarajevo that day in 1914 and not been assassinated; was the First World War inevitable?
What if the Icelandic volcano Eyjafjallajokull had not erupted in 2010? It’s perhaps the greatest counter-factual in modern European football history. Pep Guardiola’s Barcelona would have been able to fly to Milan for its Champions League semifinal first leg, rather than taking the bus.