Factual error: Towards the end of the film when Brian Clough goes to see Peter Taylor at his house in Brighton, there is a 'Pay & Display' ticket machine visible in the car park in the background. The film-makers have done a good job at placing period vehicles in shot but seem to have forgotten the shiny black new (solar powered?) ticket machine.
Factual error: When Clough and Taylor are driving off to sign Dave Mackay, you can see a Ford Capri in a driveway. This was set in 1968, and these cars didn't go on sale until a year later.
Factual error: When Leeds United arrive at the baseball ground in 1968 there is an extra with a JD Sports bag on his back. JD Sports was founded in 1981.