Sattin has agreed to become head of documentaries for the Touching the Voidproducer and will take up the role of head of documentaries, reporting to Darlow head of factual Tom Brisley.
As a result, Sattin's indie, Principal, will be shelved with the majority of its 14 permanent staff and production and development slate moving over to Darlow Smithson.
Principal's existing productions include The Real Phil Spectorfor Channel 4 and Roman Vicefor The History Channel in the US.
Sattin said the move would allow him to concentrate on programme-making. "I no longer wanted to run a production company. As a small or medium-sized indie you are competing against the bigger indies in a market for which you are not equipped."
Meanwhile, Darlow Smithson is building on the success of Touching the Voidby setting up a film division headed by former FilmFour deputy head of production Elinor Day. The division has secured£250,000 of National Lottery cash from the Film Council's development fund.