Pablo Casals Rehearses With The London Philharmonic Orchestra. Pablo Casals, the world famous cellist pictured this morning (Tuesday) conducting his first rehearsal with the London Philharmonic Orchestra, at the Royal Festival Hall, London. He was preparing the Orchestra for the performance of his own oratorio, El Pessebre (The Manger), being given at the Royal Festival Hall next Sunday, September 29. At this morning's rehearsal he met Sir Adrian Boult, who is known as the 'father' of the London Philharmonic. September 24, 1953. (Photo by Reuterphoto).