As would be the case for many people of my generation, my starting point for this film was Ken Russell's Song of Summer, which was a drama about Delius's final years. I think it is the best composer film that Russell ever made. It relies very heavily on the book by Eric Fenby, Delius As I Knew Him, where Fenby describes going over to France and getting drawn into this extraordinary nursing process. Delius was quite a depressive man and was blind and paralysed for the final period of his life – it is an immensely powerful story.
The end of Delius's life is very well documented but the early part of his life is relatively unknown. If you compare the documentation that he left to that of other composers I've made films about – Elgar and Britten – both of them were meticulous in keeping letters and recording every single day of their lives. But with Delius there are great chunks of his life where we know virtually nothing. So it's fascinating to try to fill in the gaps.