BBC3 will have an annual programme budget of £97 million and its launch will put considerable pressure on commercial stations such as E4 and Sky One, which both target young adults.
Industry estimates suggest BBC3 could cost the commercial TV stations between £7 million and £25 million in lost advertising revenue.
Jowell has attempted to assuage the fears of commercial broadcasters by imposing a number of specific conditions. These include stipulations that 80 per cent of the service's output must consist of programmes specifically commissioned for BBC3 and genuinely new to television.
The BBC chairman, Gavyn Davies, said: "BBC3 must be a high-quality and distinctive public service channel and we shall ensure that these conditions are met."