Rob Shearman, the writer of the FANtastic (YMMV) “Dalek” episode of Who gave an online interview to fans shortly after the show went out. He had this to say on the subject of writing speeches for Christopher E

“Well, it was a worry to start with. We’d all been sent what Russell had so far written – and that was Rose, in which he plays a more enigmatic mysterious role. … I just wrote an imaginary Doctor the way I hoped he’d be, whilst being aware of the different rhythms of speech Russell had given him – his greater colloquial use, for example. Once Chris was cast, it got more refined. And I listened to that Orbital track ‘You Lot’ a great deal whilst writing the Doctor’s big speeches!”