When Brian Epstein set foot in the Cavern Club in November 1961 to watch The Beatles perform, he saw something no one else could – a glimmer of gold. Sharply dressed and well-spoken, Brian was hardly the most obvious radical – but being Jewish, closeted and having grown up as an outsider who had failed at pretty much everything, he was a 26-year old with something to prove and who wanted to tear up the rulebook.