The director’s new documentary weaves together hours of unseen footage to dispel many myths about the band’s final months. John Harris, who was involved in the project, tells the inside story

On paper, the idea looked brilliant. In the opening weeks of January 1969, the Beatles were working up new songs for a televised concert, and being filmed as they did so. Where the event would take place was unclear – but as rehearsals at Twickenham film studios went on, one of their associates came up with the idea of travelling to Libya, where they would perform in the remains of a famous amphitheatre, part of an ancient Roman city called Sabratha. As the plan was discussed amid set designs and maps one Wednesday afternoon, a new element was added: why not invite a few hundred fans to join them on a specially chartered ocean liner?

Over the previous few days, John Lennon had been quiet and withdrawn, but now he seemed to be brimming with enthusiasm. The ship, he said, could be the setting for final dress rehearsals. He envisaged the group timing their set so they fell into a carefully picked musical moment just as the sun came up over the Mediterranean. If the four of them had been wondering how to present their performance, here was the most gloriously simple of answers: “God’s the gimmick,” he enthused.