Esteemed British trainer Henry Cecil has hit out at a soon-to-be-published biography that contains "unhappy and difficult phases" of his life, saying the concept of the book was changed without his authorisation.

The 70-year-old Cecil, who trained retired flat-racing great Frankel and is a 10-time champion trainer, gave British journalist Brough Scott unparalleled access to his family, friends and staff but "made it clear that it was not to include certain areas of my life".

Cecil says on his personal website the result has been "so upsetting and hurtful for my family," and is refusing to sign copies of the book.

Scott said he was "disappointed and sad" at the comments of Cecil, who was diagnosed with stomach cancer in 2006.