McLaren's painful and expensive journey back to Mercedes explained

McLaren will once again run Mercedes engines in its Formula 1 cars in 2021, after a forgettable period in which its gamble on Honda failed, and the quality of its cars were brutally exposed. We take a look at the reasons a return to Mercedes was the team's preferred option, and how the struggles with Honda were not the only thing holding it back after it left Mercedes for 2015.